How many players are in Major League Baseball?

Major League Baseball rosters aren’t as big as NFL rosters nor as small as NBA or NHL rosters. There are two types of rosters in big-league baseball: the 40-man and 25-man. According to MLB.com, the 40-man roster consists of active team members, as well as players on the injured list, the bereavement/family medical emergency list and the paternity leave list. In addition, minor league players can be included on the 40-man roster.  

Twenty-five-man rosters consist of active members on a team. Considering there are 30 teams in Major League Baseball, and 25 active men to a team, that means there are usually 750 active players. 

What is the doubleheader rule? 

There are cases where there are more than 25 players on a MLB roster. According to Baseball Reference, in November 2011, MLB’s new collective bargaining agreement allowed teams to add an extra player "on any day where two games are scheduled." This was put into effect at the start of the 2012 season. Teams can take advantage of the extra roster spot from opening day through Aug. 31, before September call-ups from the minor leagues are allowed.

What are September call-ups?

In the last month of the regular season, all 30 teams’ rosters can increase. All 40 men on MLB rosters are eligible to be used during a major league game. This creates opportunities for minor league players as well as late-season acquisitions. The roster expansion coincides with the end of the minor league baseball season for major league affiliates. While not every team takes advantage of the opportunity to have 40 players ready to play, almost all of them add players to their rosters.