Six players begin a game for each team in a volleyball match. Players who do not start but who are in uniform and available for play are substitutes. Teams may have a total of 12 players per match, although in international competitions governed by the International Volleyball Federation, they are allowed 15. They may have one libero replacement and eight substitutes or nine substitutes--libero replacements do not count as substitutes. The coach of a team decides when and whom to substitute.
A team may make a total of six acts of substitutions in a set, which can involve a total of 12 player substitutions. In other words, during one act of substitution, several players may come into the game to replace others, but once there have been 12 total substitutions, the team has reached its limit. Substitutions include those made before the set begins.
One or more players may be substituted at the same time, but a player being replaced may only return once during the set and must re-enter into his previous position. The substitute may only enter the game once and, if replaced, must be replaced by the same player whose position he took.
If a player is injured during play, a substitute may be brought in as in normal play; however, if this is not possible--for instance, if a team has used all of its allotted substitutions--an exception is allowed. In this case, any player may be brought in to replace the injured player, without penalty to the team. The injured player is not allowed to return to the match.
Players Removed from Play
If a player on the court is disqualified or expelled, he must be substituted in the normal way. If this is not possible, the team is deemed incomplete. There is no exception as there is for an injury.
Players must be on the roster to act as substitutes. They must have legal numbers and uniforms, cannot have been expelled or disqualified during the match, and cannot be replaced by players used in exceptional substitutions.
An area on the court is designated a substitution area, which is where substitutions must be carried out. The substitution must not delay the game needlessly: It should last only as long as it takes to record the action on the score sheet and for the players to exchange positions. If more than one substitution is being made at one time, they must be done in succession to limit the amount of time it takes. A team can be penalized for delays.
When a libero is replaced, it is not counted against the team's allowed substitutions, but it must be done after at least one rally has been completed.