Major League Baseball rosters

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.

(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.)

[1] Teams are also allowed an additional active player for games played at neutral sites, such as the MLB Little League Classic.

The agreement also introduced a playing rule placing severe limits on pitching by position players.

The 40-man roster limit has been in effect since 1921, except for 1945 and 1946 when it was raised to 48 to accommodate veterans returning from military service in World War II, from 1962 to 1965 when it was raised to 41 to add a reserve spot for first-year players acquired before implementation of a player draft was approved prior to the 1965 season, and in 1994 for a strike that canceled the remainder of that season.

Thus, any player on the expanded roster on September 1 or later could play for the MLB team through the end of the regular season.

There were exceptions – for example; during the 2018 season, the Los Angeles Dodgers and Philadelphia Phillies used their full rosters,[10] and in 2019 the Boston Red Sox carried 36 players (including 21 pitchers).

deemed to be a conflict of interest, Major League Baseball, which owned the Expos at the time, refused to allow them to call any players up,[12] claiming they could not afford the additional expenses.

Shortly after the decision to curtail September roster expansion was announced, former Milwaukee Brewers general manager Doug Melvin, who had advocated changes to September roster rules for more than a decade, made the following remarks to a USA Today writer:[10] I think people got sick of me talking about it, but it was about the integrity of the game....

Players who are part of the team's final roster at the end of the regular season are eligible to participate in the postseason.

Any player who has been traded from a different team, spent time in the Minor Leagues, or signed later in the season with the team (no later than August 31) is eligible to participate in the postseason; players who are suspended for drug use are not allowed to participate in the postseason.

All other professional players affiliated with Major League Baseball are signed to minor-league contracts.

The veteran player is usually signed to a "two-way" salary option – one for their time in the minors and another if they are placed on the 40-man during the season.

All spring training invitees are under some sort of contract, to avoid liability if an injury were to occur to the player.

Since 1933, an annual Major League Baseball All-Star Game has been played at approximately the mid-point of each season, except for 1945 and 2020.