<Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (September 2010) (Learn how and when to remove this template message) </Td> </Tr> <P> A Major League Baseball roster is a roster of players allowed by league agreement to play for their respective Major League Baseball team . There are two types of rosters in general, the "active roster" of 25 players and the "expanded roster" of 40 players . </P> <P> 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 - 1989 when the limit was made 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 between the major leagues and the Major League Baseball Players Association . Since 1977 teams have been required to carry a minimum of 24 players on their active rosters as well . </P> <P> Active rosters include the starting eight (NL) or nine (AL) position players, pitchers, 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 . </P>

When does mlb go to 25 man roster