Editing Baseball rules (section)

===Rosters===
The number of players on a major league roster is dictated by the labor agreements worked out between players and management. According to prior rules, a team may have a maximum of 25 men on a roster from Opening Day until August 31. Beginning in the 2012 season, a major league team was allowed to carry a 26th man on its roster when playing the second game of a double-header that was scheduled at least 48 hours in advance. As of 2020, the number has been increased to 26, of whom no more than 14 may be pitchers, with 27 for a doubleheader.

After August 31, during the regular season teams may call up additional personnel to the active roster, up to a maximum of 40 players. This number is rarely actually approached, however, with most teams' September rosters peaking at around 30 players. In 2020, the number was limited to 28.

In the postseason, rosters are fixed at 25 men. Until 2007, teams could not replace players on their playoff rosters in the event of an injury and had to play out the series shorthanded. Starting in 2007, an injured player could be placed on the disabled list and replaced by another player who was not included on the initial 25-man roster, but the injured player becomes available for the next round of the playoffs should his team advance. This rule applies in most circumstances.