Base on balls in the context of "Fielding team (baseball)"

Baseball is a bat-and-ball sport played between two teams of nine players each, taking turns batting and fielding. The game occurs over the course of several plays, with each play beginning when a player on the fielding team, called the pitcher, throws a ball that a player on the batting team, called the batter, tries to hit with a bat. The objective of the offensive team (batting team) is to hit the ball into the field of play, away from the other team's players, allowing its players to run the bases, having them advance counter-clockwise around four bases to score what are called "runs". The objective of the defensive team (referred to as the fielding team) is to prevent batters from becoming runners, and to prevent runners advancing around the bases. A run is scored when a runner legally advances around the bases in order and touches home plate (the place where the player started as a batter).

The initial objective of the batting team is to have a player reach first base safely; this occurs either when the batter hits the ball and reaches first base before an opponent retrieves the ball and touches the base, or when the pitcher persists in throwing the ball out of the batter's reach. Players on the batting team who reach first base without being called "out" can attempt to advance to subsequent bases as a runner, either immediately or during teammates' turns batting. The fielding team tries to prevent runs by using the ball to get batters or runners "out", which forces them out of the field of play. The pitcher can get the batter out by throwing three pitches which result in strikes, while fielders can get the batter out by catching a batted ball before it touches the ground, and can get a runner out by tagging them with the ball while the runner is not touching a base.

In baseball, the pitcher is the player who throws ("pitches") the baseball from the pitcher's mound toward the catcher to begin each play, with the goal of retiring a batter, who attempts to either make contact with the pitched ball or draw a walk. In the defensive numbering system used in baseball, the pitcher is assigned the number 1. The pitcher is often considered the most important player on the defensive side of the game, and as such is situated at the right end of the defensive spectrum. There are many different types of pitchers, such as the starting pitcher, relief pitcher, middle reliever, lefty specialist, setup man, and the closer.

Traditionally, the pitcher also bats. Starting in 1973 with the American League and spreading to further leagues throughout the 1980s and 1990s, the hitting duties of the pitcher have generally been given over to the position of designated hitter, a cause of some controversy. The National League adopted the designated hitter in 2022; as of 2025, the Japanese Central League is the highest level of competition to not use the designated hitter position.

In baseball, the strike zone is the area of space through which a pitch must pass in order to be called a strike even if the batter does not swing. The strike zone is defined as the volume of space above home plate and between the batter's knees and the midpoint of his torso. Whether a pitch passes through the zone is decided by an umpire, who is generally positioned behind the catcher.

Strikes are desirable for the pitcher and the fielding team, as three strikes result in a strikeout of that batter. A pitch that misses the strike zone is called a ball if the batter does not swing at it. Balls are desirable for the batter and the batting team, as four balls allow the batter to take a "walk" to first base as a base on balls.

In baseball, a player is credited with a plate appearance (denoted by PA) each time he completes a turn batting. Under Rule 5.04(c) of the Official Baseball Rules, a player completes a turn batting when he is put out or becomes a runner. This happens when he strikes out or is declared out before reaching first base; or when he reaches first base safely or is awarded first base (by a base on balls, hit by pitch, catcher's interference, or obstruction); or when he hits a fair ball which causes a preceding runner to be put out for the third out before he himself is put out or reaches first base safely (see also left on base, fielder's choice, force play). A very similar baseball statistic, at bats, counts a subset of plate appearances that end under certain circumstances.