Players, substitutes and teams and teammates

Naismith's original rules did not specify how many players were to be on the court. In 1900, five players became standard, and players that were substituted were not allowed to re-enter the game. Players were allowed to re-enter a game once from 1921, and twice from 1934; such restrictions on substitutions were abolished in 1945 when substitutions became unlimited. Coaching was originally prohibited during the game, but from 1949, coaches were allowed to address players during a time-out.

Originally a player was disqualified on his second foul. This limit became four fouls in 1911 and five fouls in 1945, still the case in most forms of basketball where the normal length of the game (before any overtime periods) is 40 minutes. When the normal length is 48 minutes (this is the case with the National Basketball Association in the United States and the National Basketball League in Australia, among others) a player is accordingly disqualified on his sixth foul,