A baseball is a shade under three inches in diameter (2.94436644720 inches, to be exact, but let's just call it three) . In a game officiated by two or more umpires, the umpire in chief(usually the home plate umpire) is the umpire who is in charge of the entire game. The home plate umpire with occasional help from the third base umpire calls balls and strikes in the game of baseball. The important thing for baseball players to do is to recognize this and understand that the strike zone may not always be exactly the same. Some umpires may have a smaller strike zone, while others will have a large strike zone. Because the definition of a strike specifies that "any part of the ball passes through [touches] any part of the strike zone" ( Definitions (strike zone) ), we can conclude that the strike zone is 23 inches wide . This umpire calls balls and strikes, calls fair balls, foul ballsshort of first/third base, and makes most calls concerning the … Some may call strikes when the ball is actually a bit wide of the plate.