who bats in the top of the inning
Inning Each half-inning formally starts when the umpire calls "Play" or "Play ball". A full inning consists of six outs, three for each team; and, in Major League Baseball and most other adult leagues, a regulation game consists of nine innings. The visiting team bats in the first half-inning, the top of the inning, derived from the position of the visiting team at the top line of a baseball line score. The home team's half of an inning is the bottom of the inning, and the break between halves of an inning is the middle of the inning. If the home team is leading in the middle of the final scheduled inning, or scores to take the lead in the bottom of the final scheduled inning, the game immediately ends in a home victory.
Batting out of turn Occasionally, one or more batters may bat in the incorrect order. In Major League Baseball, this violates rule 6.01(a) of the Official Baseball Rules. Batting out of turn is ignored by rule unless a member of the defensive team notifies the umpire that an infraction has occurred. Once the umpire is notified, he enforces the rule based on the batting order he had received.