Ballpark arbiters, or umpires (4 letters), are responsible for officiating baseball games. They make sure the rules of the game are followed and that the players abide by them. Umpires also make decisions on plays that are not covered by the rules, such as whether a batted ball is fair or foul. Umpires also have the authority to eject players from the game if they are deemed to be in violation of the rules.