baseball

Baseball is a bat-and-ball game played between two teams of nine players who take turns batting and fielding. The offense attempts to score runs by hitting a ball thrown by the pitcher with a bat and moving counter-clockwise around a series of four bases: first, second, third and home plate. A run is scored when the runner advances around the bases and returns to home plate.

Players on the batting team take turns hitting against the pitcher of the fielding team, which tries to prevent runs by getting hitters out in any of several ways. A player on the batting team can stop at any of the bases and later advance on a teammate's hit or other means. The teams switch between batting and fielding whenever the fielding team records three outs. One turn at bat for both teams, beginning with the visiting team, constitutes an inning, and nine innings a game. The team with the greater number of runs at the end of the game wins.

Evolving from older bat-and-ball games, an early form of baseball was being played in England by the mid-18th century. This game was brought by immigrants to North America, where the modern version developed. By the late 19th century, baseball was widely recognized as the national sport of the United States. Baseball is now popular in North America and parts of Central and South America and the Caribbean, East Asia and Europe.

In the United States and Canada, professional Major League Baseball (MLB) teams are divided into the National League (NL) and American League (AL), each with three divisions: East, West, and Central. The major league champion is determined by playoffs that culminate in the World Series. The top level of play is similarly split in Japan between the Central League and Pacific Leagues and in Cuba between the West League and East League.

History
Origins of baseball
The evolution of baseball from older bat-and-ball games is difficult to trace with precision. A French manuscript from 1344 contains an illustration of clerics playing a game, possibly la soule, with similarities to baseball. Other old French games such as theque, la balle au baton, and la balle empoisonnee also appear to be related. Consensus once held that today's baseball is a North American development from the older game rounders, popular in Great Britain and Ireland. Baseball Before We Knew It: A Search for the Roots of the Game (2005), by David Block, suggests that the game originated in England; recently uncovered historical evidence supports this position. Block argues that rounders and early baseball were actually regional variants of each other, and that the game's most direct antecedents are the English games of stoolball and "tut-ball". It has long been believed that cricket also descended from such games, though evidence uncovered in early 2009 suggests that the sport may have been imported to England from Flanders.

The earliest known reference to baseball is in a 1744 British publication, A Little Pretty Pocket-Book, by John Newbery. It contains a rhymed description of "base-ball" and a woodcut that shows a field set-up somewhat similar to the modern game-though in a triangular rather than diamond configuration, and with posts instead of ground-level bases. David Block discovered that the first recorded game of "Bass-Ball" took place in 1749 in Surrey, and featured the Prince of Wales as a player. William Bray, an English lawyer, recorded a game of baseball on Easter Monday 1755 in Guildford, Surrey. This early form of the game was apparently brought to North America by English immigrants. Rounders was also brought to the continent by both British and Irish immigrants. The first known American reference to baseball appears in a 1791 Pittsfield, Massachusetts, town bylaw prohibiting the playing of the game near the town's new meeting house. By 1796, a version of the game was well-known enough to earn a mention in a German scholar's book on popular pastimes. As described by Johann Gutsmuths, "englische Base-ball" involved a contest between two teams, in which "the batter has three attempts to hit the ball while at the home plate." Only one out was required to retire a side.

By the early 1830s, there were reports of a variety of uncodified bat-and-ball games recognizable as early forms of baseball being played around North America. These games were often referred to locally as "town ball", though other names such as "round-ball" and "base-ball" were also used. Among the earliest examples to receive a detailed description-albeit five decades after the fact, in a letter from an attendee to Sporting Life magazine-took place in Beachville, Ontario, in 1838. There were many similarities to modern baseball, and some crucial differences: five bases (or byes); first bye just 18 feet (5.5 m) from the home bye; batter out if a hit ball was caught after the first bounce. The once widely accepted story that Abner Doubleday invented baseball in Cooperstown, New York, in 1839 has been conclusively debunked by sports historians.

In 1845, Alexander Cartwright, a member of New York City's Knickerbockers club, led the codification of the so-called Knickerbocker Rules. The practice, common to bat-and-ball games of the day, of "soaking" or "plugging"-effecting a putout by hitting a runner with a thrown ball-was barred. The rules thus facilitated the use of a smaller, harder ball than had been common. Several other rules also brought the Knickerbockers' game close to the modern one, though a ball caught on the first bounce was, again, an out and only underhand pitching was allowed. While there are reports that the New York Knickerbockers played games in 1845, the contest now recognized as the first officially recorded baseball game in U.S. history took place on June 19, 1846, in Hoboken, New Jersey: the "New York Nine" defeated the Knickerbockers, 23-1, in four innings. With the Knickerbocker code as the basis, the rules of modern baseball continued to evolve over the next half-century.

History of baseball in the United States
The game turns professional
In the mid-1850s, a baseball craze hit the New York metropolitan area. By 1856, local journals were referring to baseball as the "national pastime" or "national game". A year later, sixteen area clubs formed the sport's first governing body, the National Association of Base Ball Players. In 1858 in Corona, Queens New York, at the Fashion Race Course, the first games of baseball to charge admission took place. The games, which took place between the all stars of Brooklyn, including players from the Brooklyn Atlantics, Excelsior of Brooklyn, Putnams and Eckford of Brooklyn, and the All Stars of New York (Manhattan), including players from the New York Knickerbockers, Gothams (predecessors of the San Francisco Giants), Eagles and Empire, are commonly believed to be the first all-star baseball games. In 1863, the organization disallowed putouts made by catching a fair ball on the first bounce. Four years later, it barred participation by African Americans. The game's commercial potential was developing: in 1869 the first fully professional baseball club, the Cincinnati Red Stockings, was formed and went undefeated against a schedule of semipro and amateur teams. The first professional league, the National Association of Professional Base Ball Players, lasted from 1871 to 1875; scholars dispute its status as a major league.

The more formally structured National League was founded in 1876. As the oldest surviving major league, the National League is sometimes referred to as the "senior circuit". Several other major leagues formed and failed. In 1884, African American Moses Walker (and, briefly, his brother Welday) played in one of these, the American Association. An injury ended Walker's major league career, and by the early 1890s, a gentlemen's agreement in the form of the baseball color line effectively barred black players from the white-owned professional leagues, major and minor. Professional Negro leagues formed, but quickly folded. Several independent African American teams succeeded as barnstormers. Also in 1884, overhand pitching was legalized. In 1887, softball, under the name of indoor baseball or indoor-outdoor, was invented as a winter version of the parent game. Virtually all of the modern baseball rules were in place by 1893; the last major change-counting foul balls as strikes-was instituted in 1901. The National League's first successful counterpart, the American League, which evolved from the minor Western League, was established that year. The two leagues, each with eight teams, were rivals that fought for the best players, often disregarding each other's contracts and engaging in bitter legal disputes.

A modicum of peace was eventually established, leading to the National Agreement of 1903. The pact formalized relations both between the two major leagues and between them and the National Association of Professional Base Ball Leagues, representing most of the country's minor professional leagues. The World Series, pitting the two major league champions against each other, was inaugurated that fall, albeit without express major league sanction: The Boston Americans of the American League defeated the Pittsburgh Pirates of the National League. The next year, the series was not held, as the National League champion New York Giants, under manager John McGraw, refused to recognize the major league status of the American League and its champion. In 1905, the Giants were National League champions again and team management relented, leading to the establishment of the World Series as the major leagues' annual championship event.

As professional baseball became increasingly profitable, players frequently raised grievances against owners over issues of control and equitable income distribution. During the major leagues' early decades, players on various teams occasionally attempted strikes, which routinely failed when their jobs were sufficiently threatened. In general, the strict rules of baseball contracts and the reserve clause, which bound players to their teams even when their contracts had ended, tended to keep the players in check. Motivated by dislike for particularly stingy owner Charles Comiskey and gamblers' payoffs, real and promised, members of the Chicago White Sox conspired to throw the 1919 World Series. The Black Sox Scandal led to the formation of a new National Commission of baseball that drew the two major leagues closer together. The first major league baseball commissioner, Kenesaw Mountain Landis, was elected in 1920. That year also saw the founding of the Negro National League; the first significant Negro league, it would operate until 1931. For part of the 1920s, it was joined by the Eastern Colored League.

Rise of Ruth and racial integration
Compared with the present, professional baseball in the early 20th century was lower scoring and pitchers, the likes of Walter Johnson and Christy Mathewson, were more dominant. The "inside game", which demanded that players "scratch for runs", was played much more aggressively than it is today: the brilliant and often violent Ty Cobb epitomized this style. The so-called dead-ball era ended in the early 1920s with several changes in rule and circumstance that were advantageous to hitters. Strict new regulations governing the ball's size, shape and composition, coupled with superior materials available after World War I, resulted in a ball that traveled farther when hit. The construction of additional seating to accommodate the rising popularity of the game often had the effect of bringing the outfield fences closer in, making home runs more common. The rise of the legendary player Babe Ruth, the first great power hitter of the new era, helped permanently alter the nature of the game. The club with which Ruth set most of his slugging records, the New York Yankees, built a reputation as the majors' premier team. In the late 1920s and early 1930s, St. Louis Cardinals general manager Branch Rickey invested in several minor league clubs and developed the first modern "farm system". A new Negro National League was organized in 1933; four years later, it was joined by the Negro American League. The first elections to the Baseball Hall of Fame took place in 1936. In 1939 Little League Baseball was founded in Pennsylvania. By the late 1940s, it was the organizing body for children's baseball leagues across the United States.

With America's entry into World War II, many professional players had left to serve in the armed forces. A large number of minor league teams disbanded as a result and the major league game seemed under threat as well. Chicago Cubs owner Philip K. Wrigley led the formation of a new professional league with women players to help keep the game in the public eye - the All-American Girls Professional Baseball League existed from 1943 to 1954. The inaugural College World Series was held in 1947, and the Babe Ruth League youth program was founded. This program soon became another important organizing body for children's baseball. The first crack in the unwritten agreement barring blacks from white-controlled professional ball occurred the previous year: Jackie Robinson was signed by the National League's Brooklyn Dodgers-where Branch Rickey had become general manager-and began playing for their minor league team in Montreal. In 1947, Robinson broke the major leagues' color barrier when he debuted with the Dodgers. Larry Doby debuted with the American League's Cleveland Indians the same year. Latin American players, largely overlooked before, also started entering the majors in greater numbers. In 1951, two Chicago White Sox, Venezuelan-born Chico Carrasquel and black Cuban-born Minnie Minoso, became the first Hispanic All-Stars.

Facing competition as varied as television and football, baseball attendance at all levels declined. While the majors rebounded by the mid-1950s, the minor leagues were gutted and hundreds of semipro and amateur teams dissolved. Integration proceeded slowly: by 1953, only six of the 16 major league teams had a black player on the roster. That year, the Major League Baseball Players Association was founded. It was the first professional baseball union to survive more than briefly, but it remained largely ineffective for years. No major league team had been located west of St. Louis until 1958, when the Brooklyn Dodgers and New York Giants relocated to Los Angeles and San Francisco, respectively. The majors' final all-white bastion, the Boston Red Sox, added a black player in 1959. With the integration of the majors drying up the available pool of players, the last Negro league folded the following year. In 1961, the American League reached the West Coast with the Los Angeles Angels expansion team, and the major league season was extended from 154 games to 162. This coincidentally helped Roger Maris break Babe Ruth's long-standing single-season home run record, one of the most celebrated marks in baseball. Along with the Angels, three other new franchises were launched during 1961-62. With this, the first major league expansion in 60 years, each league now had ten teams.

Attendance records and the age of steroids
The players' union became bolder under the leadership of former United Steelworkers chief economist and negotiator Marvin Miller, who was elected executive director in 1966. On the playing field, major league pitchers were becoming increasingly dominant again. After the 1968 season, in an effort to restore balance, the strike zone was reduced and the height of the pitcher's mound was lowered from 15 to 10 inches. In 1969, both the National and American leagues added two more expansion teams, the leagues were reorganized into two divisions each, and a post-season playoff system leading to the World Series was instituted. Also that same year, Curt Flood of the St. Louis Cardinals made the first serious legal challenge to the reserve clause. The major leagues' first general players' strike took place in 1972. In another effort to add more offense to the game, the American League adopted the designated hitter rule the following year. In 1975, the union's power-and players' salaries-began to increase greatly when the reserve clause was effectively struck down, leading to the free agency system. In 1977, two more expansion teams joined the American League. Significant work stoppages occurred again in 1981 and 1994, the latter forcing the cancellation of the World Series for the first time in 90 years. Attendance had been growing steadily since the mid-1970s and in 1994, before the stoppage, the majors were setting their all-time record for per-game attendance.

The addition of two more expansion teams after the 1993 season had facilitated another restructuring of the major leagues, this time into three divisions each. Offensive production-the number of home runs in particular-had surged that year, and again in the abbreviated 1994 season. After play resumed in 1995, this trend continued and non-division-winning wild card teams became a permanent fixture of the post-season. Regular-season interleague play was introduced in 1997 and the second-highest attendance mark for a full season was set.The next year, Mark McGwire and Sammy Sosa both surpassed Maris's decades-old single season home run record and two more expansion franchises were added. In 2000, the National and American leagues were dissolved as legal entities. While their identities were maintained for scheduling purposes (and the designated hitter distinction), the regulations and other functions-such as player discipline and umpire supervision-they had administered separately were consolidated under the rubric of Major League Baseball (MLB).

In 2001, Barry Bonds established the current record of 73 home runs in a single season. There had long been suspicions that the dramatic increase in power hitting was fueled in large part by the abuse of illegal steroids (as well as by the dilution of pitching talent due to expansion), but the issue only began attracting significant media attention in 2002 and there was no penalty for the use of performance-enhancing drugs before 2004. In 2007, Bonds became MLB's all-time home run leader, surpassing Hank Aaron, as total major league and minor league attendance both reached all-time highs. Even though McGwire, Sosa, and Bonds-as well as many other players, including storied pitcher Roger Clemens-have been implicated in the steroid abuse scandal, their feats and those of other sluggers had become the major leagues' defining attraction. In contrast to the professional game's resurgence in popularity after the 1994 interruption, Little League enrollment was in decline: after peaking in 1996, it dropped 1 percent a year over the following decade. With more rigorous testing and penalties for performance-enhancing drug use a possible factor, the balance between bat and ball swung markedly in 2010, which became known as the "Year of the Pitcher". Runs per game fell to their lowest level in 18 years, and the strikeout rate was higher than it had been in half a century. Before the start of the 2012 season, MLB altered its rules to double the number of wild card teams admitted into the playoffs to two per league.

Baseball around the world
Baseball, widely known as America's pastime, is well established in several other countries as well. The history of baseball in Canada has remained closely linked with that of the sport in the United States. As early as 1877, a professional league, the International Association, featured teams from both countries. While baseball is widely played in Canada and many minor league teams have been based in the country, the American major leagues did not include a Canadian club until 1969, when the Montreal Expos joined the National League as an expansion team. In 1977, the expansion Toronto Blue Jays joined the American League. The Blue Jays won the World Series in 1992 and 1993, the first and still the only club from outside the United States to do so. After the 2004 season, Major League Baseball relocated the Expos to Washington, D.C., where the team is now known as the Nationals.

In 1847, American soldiers played what may have been the first baseball game in Mexico at Parque Los Berros in Xalapa, Veracruz. A few days after the Battle of Cerro Gordo, they used the "wooden leg captured (by the Fourth Illinois regiment) from General Santa Anna". The first formal baseball league outside of the United States and Canada was founded in 1878 in Cuba, which maintains a rich baseball tradition and whose national team has been one of the world's strongest since international play began in the late 1930s (all organized baseball in the country has officially been amateur since the Cuban Revolution). The Dominican Republic held its first islandwide championship tournament in 1912. Professional baseball tournaments and leagues began to form in other countries between the world wars, including the Netherlands (formed in 1922), Australia (1934), Japan (1936), Mexico (1937), and Puerto Rico (1938). The Japanese major leagues-the Central League and Pacific League-have long been considered the highest quality professional circuits outside of the United States. Japan has a professional minor league system as well, though it is much smaller than the American version-each team has only one farm club in contrast to MLB teams' four or five.

After World War II, professional leagues were founded in many Latin American nations, most prominently Venezuela (1946) and the Dominican Republic (1955). Since the early 1970s, the annual Caribbean Series has matched the championship clubs from the four leading Latin American winter leagues: the Dominican Winter League, Mexican Pacific League, Puerto Rican Professional Baseball League, and Venezuelan Professional Baseball League. In Asia, South Korea (1982), Taiwan (1990), and China (2003) all have professional leagues.

Many European countries have professional leagues as well, the most successful, other than the Dutch league, being the Italian league founded in 1948. Compared to those in Asia and Latin America, the various European leagues and the one in Australia historically have had no more than niche appeal. In 2004, Australia won a surprise silver medal at the Olympic Games. The Israel Baseball League, launched in 2007, folded after one season. The Confederation Europeene de Baseball (European Baseball Confederation), founded in 1953, organizes a number of competitions between clubs from different countries, as well as national squads. Other competitions between national teams, such as the Baseball World Cup and the Olympic baseball tournament, were administered by the International Baseball Federation (IBAF) from its formation in 1938 until its 2013 merger with the International Softball Federation to create the current joint governing body for both sports, the World Baseball Softball Confederation (WBSC). By 2009, the IBAF had 117 member countries. Women's baseball is played on an organized amateur basis in many of the countries where it is a leading men's sport. Since 2004, the IBAF and now WBSC have sanctioned the Women's Baseball World Cup, featuring national teams.

After being admitted to the Olympics as a medal sport beginning with the 1992 Games, baseball was dropped from the 2012 Summer Olympic Games at the 2005 International Olympic Committee meeting. It remained part of the 2008 Games. The elimination of baseball, along with softball, from the 2012 Olympic program enabled the IOC to consider adding two different sports, but none received the votes required for inclusion. While the sport's lack of a following in much of the world was a factor, more important was Major League Baseball's reluctance to have a break during the Games to allow its players to participate, as the National Hockey League now does during the Winter Olympic Games. Such a break is more difficult for MLB to accommodate because it would force the playoffs deeper into cold weather. Seeking reinstatement for the 2016 Summer Olympics, the IBAF proposed an abbreviated competition designed to facilitate the participation of top players, but the effort failed.Major League Baseball initiated the World Baseball Classic, scheduled to precede the major league season, partly as a replacement, high-profile international tournament. The inaugural Classic, held in March 2006, was the first tournament involving national teams to feature a significant number of MLB participants. The Baseball World Cup was discontinued after its 2011 edition in favor of an expanded World Baseball Classic.

Rules and gameplay
A game is played between two teams, each composed of nine players, that take turns playing offense (batting and baserunning) and defense (pitching and fielding). A pair of turns, one at bat and one in the field, by each team constitutes an inning. A game consists of nine innings. One team-customarily the visiting team-bats in the top, or first half, of every inning. The other team-customarily the home team-bats in the bottom, or second half, of every inning. The goal of the game is to score more points (runs) than the other team. The players on the team at bat attempt to score runs by circling or completing a tour of the four bases set at the corners of the square-shaped baseball diamond. A player bats at home plate and must proceed counterclockwise to first base, second base, third base, and back home in order to score a run. The team in the field attempts both to prevent runs from scoring and to record outs, which remove opposing players from offensive action until their turn in their team's batting order comes up again. When three outs are recorded, the teams switch roles for the next half-inning. If the score of the game is tied after nine innings, extra innings are played to resolve the contest. Many amateur games, particularly unorganized ones, involve different numbers of players and innings.

The game is played on a field whose primary boundaries, the foul lines, extend forward from home plate at 45-degree angles. The 90-degree area within the foul lines is referred to as fair territory; the 270-degree area outside them is foul territory. The part of the field enclosed by the bases and several yards beyond them is the infield; the area farther beyond the infield is the outfield. In the middle of the infield is a raised pitcher's mound, with a rectangular rubber plate (the rubber) at its center. The outer boundary of the outfield is typically demarcated by a raised fence, which may be of any material and height (many amateur games are played on unfenced fields). Fair territory between home plate and the outfield boundary is baseball's field of play, though significant events can take place in foul territory, as well.

There are three basic tools of baseball: the ball, the bat, and the glove or mitt:

Protective helmets are also standard equipment for all batters.

At the beginning of each half-inning, the nine players on the fielding team arrange themselves around the field. One of them, the pitcher, stands on the pitcher's mound. The pitcher begins the pitching delivery with one foot on the rubber, pushing off it to gain velocity when throwing toward home plate. Another player, the catcher, squats on the far side of home plate, facing the pitcher. The rest of the team faces home plate, typically arranged as four infielders-who set up along or within a few yards outside the imaginary lines between first, second, and third base-and three outfielders. In the standard arrangement, there is a first baseman positioned several steps to the left of first base, a second baseman to the right of second base, a shortstop to the left of second base, and a third baseman to the right of third base. The basic outfield positions are left fielder, center fielder, and right fielder. A neutral umpire sets up behind the catcher. Other umpires will be distributed around the field as well, though the number will vary depending on the level of play, amateur or children's games may only have an umpire behind the plate, while as many as six umpires can be used for important Major League Baseball games.

Play starts with a batter standing at home plate, holding a bat. The batter waits for the pitcher to throw a pitch (the ball) toward home plate, and attempts to hit the ball with the bat. The catcher catches pitches that the batter does not hit-as a result of either electing not to swing or failing to connect-and returns them to the pitcher. A batter who hits the ball into the field of play must drop the bat and begin running toward first base, at which point the player is referred to as a runner (or, until the play is over, a batter-runner). A batter-runner who reaches first base without being put out (see below) is said to be safe and is now on base. A batter-runner may choose to remain at first base or attempt to advance to second base or even beyond-however far the player believes can be reached safely. A player who reaches base despite proper play by the fielders has recorded a hit. A player who reaches first base safely on a hit is credited with a single. If a player makes it to second base safely as a direct result of a hit, it is a double; third base, a triple. If the ball is hit in the air within the foul lines over the entire outfield (and outfield fence, if there is one), it is a home run: the batter and any runners on base may all freely circle the bases, each scoring a run. This is the most desirable result for the batter. A player who reaches base due to a fielding mistake is not credited with a hit-instead, the responsible fielder is charged with an error.

Any runners already on base may attempt to advance on batted balls that land, or contact the ground, in fair territory, before or after the ball lands. A runner on first base must attempt to advance if a ball lands in play. If a ball hit into play rolls foul before passing through the infield, it becomes dead and any runners must return to the base they were at when the play began. If the ball is hit in the air and caught before it lands, the batter has flied out and any runners on base may attempt to advance only if they tag up or touch the base they were at when the play began, as or after the ball is caught. Runners may also attempt to advance to the next base while the pitcher is in the process of delivering the ball to home plate-a successful effort is a stolen base.

A pitch that is not hit into the field of play is called either a strike or a ball. A batter against whom three strikes are recorded strikes out. A batter against whom four balls are recorded is awarded a base on balls or walk, a free advance to first base. (A batter may also freely advance to first base if the batter's body or uniform is struck by a pitch outside the strike zone, provided the batter does not swing and attempts to avoid being hit.) Crucial to determining balls and strikes is the umpire's judgment as to whether a pitch has passed through the strike zone, a conceptual area above home plate extending from the midpoint between the batter's shoulders and belt down to the hollow of the knee.

A strike is called when one of the following happens: A ball is called when the pitcher throws a pitch that is outside the strike zone, provided the batter has not swung at it.

While the team at bat is trying to score runs, the team in the field is attempting to record outs. Among the various ways a member of the batting team may be put out, five are most common: It is possible to record two outs in the course of the same play-a double play. Even three-a triple play-is possible, though this is very rare. Players put out or retired must leave the field, returning to their team's dugout or bench. A runner may be stranded on base when a third out is recorded against another player on the team. Stranded runners do not benefit the team in its next turn at bat-every half-inning begins with the bases empty of runners.

An individual player's turn batting or plate appearance is complete when the player reaches base, hits a home run, makes an out, or hits a ball that results in the team's third out, even if it is recorded against a teammate. On rare occasions, a batter may be at the plate when, without the batter's hitting the ball, a third out is recorded against a teammate-for instance, a runner getting caught stealing (tagged out attempting to steal a base). A batter with this sort of incomplete plate appearance starts off the team's next turn batting; any balls or strikes recorded against the batter the previous inning are erased. A runner may circle the bases only once per plate appearance and thus can score at most a single run per batting turn. Once a player has completed a plate appearance, that player may not bat again until the eight other members of the player's team have all taken their turn at bat. The batting order is set before the game begins, and may not be altered except for substitutions. Once a player has been removed for a substitute, that player may not reenter the game. Children's games often have more liberal substitution rules.

If the designated hitter (DH) rule is in effect, each team has a tenth player whose sole responsibility is to bat (and run). The DH takes the place of another player-almost invariably the pitcher-in the batting order, but does not field. Thus, even with the DH, each team still has a batting order of nine players and a fielding arrangement of nine players.

Personnel
Player rosters
Roster, or squad, sizes differ between different leagues and different levels of organized play. Major League Baseball teams maintain 25-player active rosters. A typical 25-man roster in a league without the DH rule, such as MLB's National League, features: Other personnel
The manager, or head coach of a team, oversees the team's major strategic decisions, such as establishing the starting rotation, setting the lineup, or batting order, before each game, and making substitutions during games-in particular, bringing in relief pitchers. Managers are typically assisted by two or more coaches; they may have specialized responsibilities, such as working with players on hitting, fielding, pitching, or strength and conditioning. At most levels of organized play, two coaches are stationed on the field when the team is at bat: the first base coach and third base coach, occupying designated coaches' boxes just outside the foul lines, assist in the direction of baserunners when the ball is in play, and relay tactical signals from the manager to batters and runners during pauses in play. In contrast to many other team sports, baseball managers and coaches generally wear their team's uniforms; coaches must be in uniform in order to be allowed on the playing field during a game.

Any baseball game involves one or more umpires, who make rulings on the outcome of each play. At a minimum, one umpire will stand behind the catcher, to have a good view of the strike zone, and call balls and strikes. Additional umpires may be stationed near the other bases, thus making it easier to judge plays such as attempted force outs and tag outs. In Major League Baseball, four umpires are used for each game, one near each base. In the playoffs, six umpires are used: one at each base and two in the outfield along the foul lines.

Strategy and tactics
Many of the pre-game and in-game strategic decisions in baseball revolve around a fundamental fact: in general, right-handed batters tend to be more successful against left-handed pitchers and, to an even greater degree, left-handed batters tend to be more successful against right-handed pitchers. A manager with several left-handed batters in the regular lineup who knows the team will be facing a left-handed starting pitcher may respond by starting one or more of the right-handed backups on the team's roster. During the late innings of a game, as relief pitchers and pinch hitters are brought in, the opposing managers will often go back and forth trying to create favorable matchups with their substitutions: the manager of the fielding team trying to arrange same-handed pitcher-batter matchups, the manager of the batting team trying to arrange opposite-handed matchups. With a team that has the lead in the late innings, a manager may remove a starting position player-especially one whose turn at bat is not likely to come up again-for a more skillful fielder.

Pitching and fielding tactics
A first baseman receives a pickoff throw, as the runner dives back to first base. The tactical decision that precedes almost every play in a baseball game involves pitch selection. Among the wide variety of pitches that may be thrown, the four basic types are the fastball, the changeup (or off-speed pitch), and two breaking balls-the curveball and the slider. Pitchers have different repertoires of pitches they are skillful at throwing. Conventionally, before each pitch, the catcher signals the pitcher what type of pitch to throw, as well as its general vertical and/or horizontal location. If there is disagreement on the selection, the pitcher may shake off the sign and the catcher will call for a different pitch. With a runner on base and taking a lead, the pitcher may attempt a pickoff, a quick throw to a fielder covering the base to keep the runner's lead in check or, optimally, effect a tag out. If an attempted stolen base is anticipated, the catcher may call for a pitchout, a ball thrown deliberately off the plate, allowing the catcher to catch it while standing and throw quickly to a base. Facing a batter with a strong tendency to hit to one side of the field, the fielding team may employ a shift, with most or all of the fielders moving to the left or right of their usual positions. With a runner on third base, the infielders may play in, moving closer to home plate to improve the odds of throwing out the runner on a ground ball, though a sharply hit grounder is more likely to carry through a drawn-in infield.

Batting and baserunning tactics
Several basic offensive tactics come into play with a runner on first base, including the fundamental choice of whether to attempt a steal of second base. The hit and run is sometimes employed with a skillful contact hitter: the runner takes off with the pitch drawing the shortstop or second baseman over to second base, creating a gap in the infield for the batter to poke the ball through. The sacrifice bunt calls for the batter to focus on making contact with the ball so that it rolls a short distance into the infield, allowing the runner to advance into scoring position even at the expense of the batter being thrown out at first-a batter who succeeds is credited with a sacrifice. (A batter, particularly one who is a fast runner, may also attempt to bunt for a hit.) A sacrifice bunt employed with a runner on third base, aimed at bringing that runner home, is known as a squeeze play. With a runner on third and fewer than two outs, a batter may instead concentrate on hitting a fly ball that, even if it is caught, will be deep enough to allow the runner to tag up and score-a successful batter in this case gets credit for a sacrifice fly. The manager will sometimes signal a batter who is ahead in the count (i.e., has more balls than strikes) to take, or not swing at, the next pitch.

Distinctive elements
Baseball has certain attributes that set it apart from the other popular team sports in the countries where it has a following, games such as American and Canadian football, basketball, ice hockey, and soccer. All of these sports use a clock; in all of them, play is less individual and more collective; and in none of them is the variation between playing fields nearly as substantial or important. The comparison between cricket and baseball demonstrates that many of baseball's distinctive elements are shared in various ways with its cousin sports.

No clock to kill
In clock-limited sports, games often end with a team that holds the lead killing the clock rather than competing aggressively against the opposing team. In contrast, baseball has no clock; a team cannot win without getting the last batter out and rallies are not constrained by time. At almost any turn in any baseball game, the most advantageous strategy is some form of aggressive strategy. In contrast, again, the clock comes into play even in the case of multi-day Test and first-class cricket: the possibility of a draw often encourages a team that is batting last and well behind to bat defensively, giving up any faint chance at a win to avoid a loss. Baseball offers no such reward for conservative batting.

While nine innings has been the standard since the beginning of professional baseball, the duration of the average major league game has increased steadily through the years. At the turn of the 20th century, games typically took an hour and a half to play. In the 1920s, they averaged just less than two hours, which eventually ballooned to 2:38 in 1960. By 1997, the average American League game lasted 2:57 (National League games were about 10 minutes shorter-pitchers at the plate making for quicker outs than designated hitters). In 2004, Major League Baseball declared that its goal was an average game of merely 2:45. The lengthening of games is attributed to longer breaks between half-innings for television commercials, increased offense, more pitching changes, and a slower pace of play with pitchers taking more time between each delivery, and batters stepping out of the box more frequently. Other leagues have experienced similar issues. In 2008, Nippon Professional Baseball took steps aimed at shortening games by 12 minutes from the preceding decade's average of 3:18.

Individual focus
For a team sport, baseball places individual players under unusual scrutiny and pressure. In 1915, a baseball instructional manual pointed out that every single pitch, of which there are often more than two hundred in a game, involves an individual, one-on-one contest: "the pitcher and the batter in a battle of wits". Contrasting the game with both football and basketball, scholar Michael Mandelbaum argues that "baseball is the one closest in evolutionary descent to the older individual sports". Pitcher, batter, and fielder all act essentially independent of each other. While coaching staffs can signal pitcher or batter to pursue certain tactics, the execution of the play itself is a series of solitary acts. If the batter hits a line drive, the outfielder is solely responsible for deciding to try to catch it or play it on the bounce and for succeeding or failing. The statistical precision of baseball is both facilitated by this isolation and reinforces it. As described by Mandelbaum,

It is impossible to isolate and objectively assess the contribution each [football] team member makes to the outcome of the play ... Every basketball player is interacting with all of his teammates all the time. In baseball, by contrast, every player is more or less on his own ... Baseball is therefore a realm of complete transparency and total responsibility. A baseball player lives in a glass house, and in a stark moral universe ... Everything that every player does is accounted for and everything accounted for is either good or bad, right or wrong.


Cricket is more similar to baseball than many other team sports in this regard: while the individual focus in cricket is mitigated by the importance of the batting partnership and the practicalities of tandem running, it is enhanced by the fact that a batsman may occupy the wicket for an hour or much more. There is no statistical equivalent in cricket for the fielding error and thus less emphasis on personal responsibility in this area of play.

Uniqueness of each baseball park
Unlike those of most sports, baseball playing fields can vary significantly in size and shape. While the dimensions of the infield are specifically regulated, the only constraint on outfield size and shape for professional teams following the rules of Major League and Minor League Baseball is that fields built or remodeled since June 1, 1958, must have a minimum distance of 325 feet (99 m) from home plate to the fences in left and right field and 400 feet (122 m) to center. Major league teams often skirt even this rule. For example, at Minute Maid Park, which became the home of the Houston Astros in 2000, the Crawford Boxes in left field are only 315 feet (96 m) from home plate. There are no rules at all that address the height of fences or other structures at the edge of the outfield. The most famously idiosyncratic outfield boundary is the left-field wall at Boston's Fenway Park, in use since 1912: the Green Monster is 310 feet (94 m) from home plate down the line and 37 feet (11 m) tall.

Fenway Park, home of the Boston Red Sox. The Green Monster is visible beyond the playing field on the left. Similarly, there are no regulations at all concerning the dimensions of foul territory. Thus a foul fly ball may be entirely out of play in a park with little space between the foul lines and the stands, but a foulout in a park with more expansive foul ground. A fence in foul territory that is close to the outfield line will tend to direct balls that strike it back toward the fielders, while one that is farther away may actually prompt more collisions, as outfielders run full speed to field balls deep in the corner. These variations can make the difference between a double and a triple or inside-the-park home run. The surface of the field is also unregulated. While the image to the left shows a traditional field surfacing arrangement (and the one used by virtually all MLB teams with naturally surfaced fields), teams are free to decide what areas will be grassed or bare. Some fields-including several in MLB-use an artificial surface, such as AstroTurf. Surface variations can have a significant effect on how ground balls behave and are fielded as well as on baserunning. Similarly, the presence of a roof (seven major league teams play in stadiums with permanent or retractable roofs) can greatly affect how fly balls are played. While football and soccer players deal with similar variations of field surface and stadium covering, the size and shape of their fields are much more standardized. The area out-of-bounds on a football or soccer field does not affect play the way foul territory in baseball does, so variations in that regard are largely insignificant.

These physical variations create a distinctive set of playing conditions at each ballpark. Other local factors, such as altitude and climate, can also significantly affect play. A given stadium may acquire a reputation as a pitcher's park or a hitter's park, if one or the other discipline notably benefits from its unique mix of elements. The most exceptional park in this regard is Coors Field, home of the Colorado Rockies. Its high altitude-5,282 feet (1,610 m) above sea level-is responsible for giving it the strongest hitter's park effect in the major leagues. Wrigley Field, home of the Chicago Cubs, is known for its fickle disposition: a hitter's park when the strong winds off Lake Michigan are blowing out, it becomes more of a pitcher's park when they are blowing in. The absence of a standardized field affects not only how particular games play out, but the nature of team rosters and players' statistical records. For example, hitting a fly ball 330 feet (100 m) into right field might result in an easy catch on the warning track at one park, and a home run at another. A team that plays in a park with a relatively short right field, such as the New York Yankees, will tend to stock its roster with left-handed pull hitters, who can best exploit it. On the individual level, a player who spends most of his career with a team that plays in a hitter's park will gain an advantage in batting statistics over time-even more so if his talents are especially suited to the park.

Statistics
Organized baseball lends itself to statistics to a greater degree than many other sports. Each play is discrete and has a relatively small number of possible outcomes. In the late 19th century, a former cricket player, English-born Henry Chadwick of Brooklyn, New York, was responsible for the "development of the box score, tabular standings, the annual baseball guide, the batting average, and most of the common statistics and tables used to describe baseball." The statistical record is so central to the game's "historical essence" that Chadwick came to be known as Father Baseball. In the 1920s, American newspapers began devoting more and more attention to baseball statistics, initiating what journalist and historian Alan Schwarz describes as a "tectonic shift in sports, as intrigue that once focused mostly on teams began to go to individual players and their statistics lines."

The Official Baseball Rules administered by Major League Baseball require the official scorer to categorize each baseball play unambiguously. The rules provide detailed criteria to promote consistency. The score report is the official basis for both the box score of the game and the relevant statistical records. General managers, managers, and baseball scouts use statistics to evaluate players and make strategic decisions.

Certain traditional statistics are familiar to most baseball fans. The basic batting statistics include: The basic baserunning statistics include: The basic pitching statistics include: The basic fielding statistics include: Among the many other statistics that are kept are those collectively known as situational statistics. For example, statistics can indicate which specific pitchers a certain batter performs best against. If a given situation statistically favors a certain batter, the manager of the fielding team may be more likely to change pitchers or have the pitcher intentionally walk the batter in order to face one who is less likely to succeed.

Sabermetrics
Sabermetrics refers to the field of baseball statistical study and the development of new statistics and analytical tools. The term is also used to refer directly to new statistics themselves. The term was coined around 1980 by one of the field's leading proponents, Bill James, and derives from the Society for American Baseball Research (SABR).

The growing popularity of sabermetrics since the early 1980s has brought more attention to two batting statistics that sabermetricians argue are much better gauges of a batter's skill than batting average: Some of the new statistics devised by sabermetricians have gained wide use: Source: Wikipedia