Major League Baseball rosters

A Major League Baseball roster is a list of players who are allowed, by league agreement, to play for a Major League Baseball (MLB) team. Each MLB team maintains two rosters: an active roster of players eligible to participate in an MLB game, and an expanded roster encompassing the active roster plus additional reserve players.

Beginning with the 2021 season, the active roster size is 26 players, and the expanded roster size is 40 players (the expanded roster is commonly referred to as the "40-man roster"). Historically, the active roster size was 25 players, with exceptions made in some seasons, most recently in 2020 when teams could have 28 active players.

Since 1910, when teams were first allowed to carry players under contract in excess of those allowed to participate in regular season games, the latter has been called the "active roster." With exceptions through the years for varying economic conditions (primarily during World War I, the Great Depression, post-World War II, and from 1986 to 1989 when the limit was set at 24 because of rising player salaries), the active roster has allowed up to 25 players to participate for a Major League team within specified dates, currently Opening Day to September 1. In 1968, the 25-player maximum for active rosters was made a part of the first collective bargaining agreement (CBA) between the major leagues and the Major League Baseball Players Association (MLBPA). Starting in 1977, teams were required to carry a minimum of 24 players on their active rosters as well.

Active rosters include the starting eight position players, starting pitching rotation, and reserve players on the team. Players on the active roster are also on the 40-man roster. These players are generally the only ones who dress in uniform and are the only ones who may take the field in a game at any time.

Typically, in modern-day play, an active roster will consist of five starting pitchers, eight relief pitchers, two catchers, six infielders, and five outfielders. Teams can vary this somewhat according to preference and circumstance, and indeed the "typical" roster makeup has changed somewhat over the years. (Starting rotations used to consist of four pitchers, not five, well into the 1970s; third-string catchers used to be much more common; many other minor variations exist.) A full-time designated hitter (DH) is usually classified as either an infielder or an outfielder, not a DH, because most DHs do play defensive positions from time to time.

Since 2012, teams have been allowed to carry one additional active player for "day-night" doubleheaders – two games scheduled on the same day, but with the stadium cleared between games, and separate tickets sold for each game – as long as the doubleheaders have been scheduled with at least 48 hours of advance notice. Teams are also allowed an additional active player for games played at neutral sites, such as the MLB Little League Classic.

On March 14, 2019, MLB and the MLBPA reached an agreement on midterm changes to the then-current CBA, with the changes officially unveiled on February 12, 2020. Two significant changes were announced, which were planned to take effect during the 2020 season:

Under the agreement, teams would be allowed 26-man active rosters from the start of the season through August 31, as well as the postseason. From September 1 to the end of the regular season, two additional players (28 total) would be active. Teams would be limited to carrying 13 pitchers, except from September 1 to the end of the regular season, when this limit would increase to 14. Prior conditions that allowed an extra active player (such as day-night doubleheaders) would persist, with the extra player not counting against the limit for pitchers.