The rules of basketball allow an unlimited number of substitutions by players during the course of the game. Substitutions are often used by coaches to provide ideal matchups against the other team, to give players rest when they are tired or to get players out of the game who are in foul trouble. Understanding the rules of basketball regarding substitution can help coaches avoid penalties.
Notifying Scorer's Table
Players must notify the scorer’s table when they wish to substitute for another player. The player must give the official scorekeeper his jersey number and wait at the scorer’s table before entering the game. The scoreboard operator is responsible for blowing the horn in order to notify the officials that a player wishes to substitute into the game. Substitutes may not enter the game until beckoned onto the floor by the officials.
Substitutes may only enter the game when the ball is dead and the clock is stopped, except during the last minute of play in college, and when the clock stops after a made basket in the National Basketball Association (NBA). Entering the game at any other time when not beckoned by the officials constitutes a technical foul. In high school, this is penalized by awarding two free throws and possession of the ball to the opposing team. In college, the opposing team simply receives two free throws, and the ball is put back in play to the team who had it last before the technical foul was called. The NBA uses the same rule as college, but only awards one free throw to the opposing team.
Free Throw, Jump Ball and Injury Situations
A player may not substitute for a free throw shooter or jumper -- a player participating in a jump ball -- unless that player is injured and unable to perform the free throw or jump ball. The player wishing to substitute must wait until the next time the ball is dead and the clock is stopped following the free throw or jump ball in order to substitute. An injured player who is entitled to a jump ball or free throw may be substituted for if she is clearly unable to perform the free throw or jump ball. In high school, the player’s coach selects a substitute for the injured player. In college and the NBA, the opposing coach is permitted to choose any member of the opposing team on the bench to substitute for the injured player.