Roster, or squad, sizes differ between different leagues and
different levels of organized play. Major League Baseball teams maintain
25-player active rosters. A typical 25-man roster in a league without
the DH rule, such as MLB's National League, features:
- eight position players—catcher, four infielders, three outfielders—who play on a regular basis
- five starting pitchers who constitute the team's pitching rotation or starting rotation
- six relief pitchers, including one specialist closer, who constitute the team's bullpen (named for the off-field area where pitchers warm up)
- one backup, or substitute, catcher
- two backup infielders
- two backup outfielders
- one specialist pinch hitter, or a second backup catcher, or a seventh reliever