In baseball, teams alternate between being fielders (defense) and batters (offense). On defense, nine players take up assigned positions on the field with the primary objective of preventing the opposing offense from scoring. The defense is tasked with collecting outs (also called putouts), which remove an opposing player from offensive play until the player’s next turn at bat. After recording three outs, the teams switch roles.

　　When a team is on offense, it strives to advance its players around the bases to score as many runs as possible, which is most often accomplished by hitting balls into fair territory (on or between the two foul lines) and out of reach of the defense. In Major League Baseball (MLB) and other professional and amateur leagues, a designated hitter (DH) is typically assigned to bat in place of the pitcher but does not take the field on defense.

　　When both teams have batted, and recorded three outs each, an inning (a division of the game consisting of a turn at bat for each team) is completed. After nine innings, the team with more runs wins the game. If there is a tie after nine innings, extra innings are played.

　　Explore the roles and responsibilities of the various fielders, batters, managers, and umpires in this interactive, then continue reading below to learn more about the object of the game and how the positions work together.

　　Defense: the battery, infielders, and outfielders

　　Mariano RiveraMariano Rivera of the New York Yankees throwing a pitch in a game against the Minnesota Twins, 2011.(more)Fielders can be grouped into three categories: the battery (pitcher and catcher); infielders (first baseman, second baseman, third baseman, and shortstop); and outfielders (left fielder, center fielder, and right fielder).

　　Get a Britannica Premium subscription and gain access to exclusive content. Subscribe Now The pitcher and catcher are core defensive players. The pitcher’s objective is to strategically throw the ball toward home plate with the goal of putting out (or retiring) the batter. The catcher is tasked with catching the pitched balls that are not hit (or those that are tipped) by the batter.

　　Most pitchers have three or four types of pitches that they usually throw during a game, such as fastballs, curveballs, sliders, changeups, sinkers, or knuckleballs. Traditionally, the catcher uses a series of finger movements to signal which pitch to throw and where to locate it. At the beginning of the 2022 season, MLB approved the use of PitchCom, a wireless communication system used by catchers, pitchers, and infielders to covertly relay pitch selection information.

　　Additionally, at the outset of the 2023 season, MLB implemented pitch timer rules to speed the pace of play. The new rules call for a 30-second time limit between batters, a 15-second time limit between pitches when the bases are empty, or a 20-second limit between pitches with runners on base. Batters must be in the batter’s box and prepared to bat with 8 seconds remaining on the pitch timer, and pitchers must start their deliveries before the timer expires. If a pitcher violates the pitch timer rules, the penalty is an automatic ball. If a batter is not prepared in time, the penalty is an automatic strike.

　　Carlton FiskChicago White Sox catcher Carlton Fisk.(more)The catcher also functions as a counselor for the pitcher and other fielders. As the only defensive player who has the playing field in front view at all times, the catcher is best placed to communicate with and direct the fielders when necessary. Additionally, the pitcher and catcher work with infielders to discourage base runners from taking a big lead (inching too far from the base they are occupying) or stealing a base (advancing without the benefit of a batted ball or a walk).

　　Roberto AlomarBaltimore Orioles second baseman Roberto Alomar extending to field a batted ball, 1997.(more)Infielders form the inner ring of defense and include middle infielders (second baseman and shortstop) and corner infielders (first baseman and third baseman). Infielders sometimes catch batted balls on the fly, but, when a ball is batted along the ground or bunted, one infielder is called upon to gain control of it, and at least one other infielder typically covers a base to receive the throw and make a putout. Infielders also work with the pitcher and catcher to discourage runners from taking big leads and stealing bases.

　　Ichiro SuzukiAmerican League All-Star Ichiro Suzuki of the Seattle Mariners making a leaping catch during the 81st MLB All-Star Game at Angel Stadium of Anaheim in California on July 13, 2010.(more)Outfielders are positioned so as to best be able to catch or field balls that are batted over or through the infield. Successful outfielders should be able to judge the trajectory of fly balls and have enough speed to run the ball down. Strong throwing arms are also important, as is accuracy in throwing the ball to the appropriate part of the infield.

　　Offense: batters, base runners, and designated hitters

　　Ken Griffey, Jr., hitting his 500th career home runKen Griffey, Jr., of the Cincinnati Reds hitting his 500th career home run, June 20, 2004.(more)The batter, positioned in the batter’s box on the first-base or third-base side of home plate, attempts to hit the pitcher’s throw. The batter’s primary goals are to help the offense score runs and to avoid making outs. When the bases are empty, batters strive to reach base safely, advance around the bases (often with the help of hits and walks from subsequent batters), and return to home plate, thus scoring a run. When there are runners occupying bases, the batter attempts to reach base safely and advance the runners around the bases and back to home plate. There are many ways for a batter to get on base and advance any runners occupying bases, but the most common ways are by drawing a walk, hitting a ball into fair territory and out of the reach of the fielders, or hitting a home run (a hit that enables the batter to circle all the bases and score a run).

　　Base runners are batters who have reached a base successfully and occupy first, second, or third base. The goal of a base runner is to advance around the bases and score a run. Base runners can attempt to advance to the next base when the batter has hit the ball into play or try to steal a base.

　　Paul MolitorPaul Molitor of the Milwaukee Brewers in the dugout during a Major League Baseball (MLB) game in 1980. Molitor was one of the most successful designated hitters in MLB history.(more)A designated hitter is a player who is assigned to bat in place of the pitcher but does not take the field on defense. Designated hitters are specialists who excel at reaching base safely, hitting for power, and advancing base runners. The rule allowing for designated hitters was adopted by MLB’s American League in 1973 and by the National League in 2022.

　　Managers

　　Earl WeaverBaltimore Orioles manager Earl Weaver, 1980.(more)A baseball manager serves as the head coach and is responsible for the day-to-day activity of a team, overseeing player training, and making strategic decisions during a game. The manager sets pitching rotations and batting lineups and counsels players during training sessions and games. As the leader of the coaching staff and players, the manager is often the most prominent and visible representative of the team.

　　On offense, managers are assisted by two on-field coaches, the first-base coach and the third-base coach. Both are responsible for relaying signals from the dugout to batters and base runners. The first-base coach is tasked with signaling whether a runner should stop at first or continue running to second base, and a third-base coach is responsible for signaling a runner to stop at second or third base or to keep running. The first-base coach also helps base runners determine an appropriate time to steal a base and alerts runners when the pitcher or catcher attempts to put them out with a pickoff throw.

　　Umpires

　　Emil JimenezLars Nootbaar of the St. Louis Cardinals reacting after home-plate umpire Emil Jimenez calls strike three in a game against the Pittsburgh Pirates at Busch Stadium in St. Louis, Missouri, September 2, 2023.(more)Umpires are officials who conduct the play of a baseball game, enforce its rules, and handle disciplinary actions. The home-plate umpire (also called the umpire in chief) is in charge of officiating the game and works with the base umpires, stationed near first, second, and third base, to make calls and render decisions on plays during the game. The home-plate umpire is primarily responsible for calling balls and strikes on the batter and calling runners safe or out at home plate. The home-plate umpire and base umpires may call hit balls foul (beyond the foul lines) or fair (on or within the foul lines). An umpire may also appeal to fellow umpires for assistance in reviewing a play.