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.