In association football, a substitute is a player who is brought on to the pitch during a match in exchange for an existing player. Substitutions are generally made to replace a player who has become tired or injured, or who is not performing well; there may also be tactical reasons such as bringing an attacker on in place of a defender when goals are needed.
The origin of football substitutes goes back to at least the early 1860s as part of English public school football games. The original use of the term "substitute" in football was to describe the replacement of players who failed to turn up for matches. For example, in 1863, a match reports states: "The Charterhouse eleven played a match in cloisters against some old Carthusians but in consequence of the non-appearance of some of those who were expected it was necessary to provide three substitutes. The subsitution of absent players happened as early as the 1850s, for example from Eton College where the term "emergencies" is used Numerous references to players acting as a "substitute" occur in soccer matches in the mid 1860s where it is not indicated whether these were replacements of absent players or of players injured during the match.
As early as the qualifying phase for the 1954 World Cup, substitutions were permitted during games, the first ever replacement being Horst Eckel of Germany during their match with the Saarland on 11 October 1953.
Substitutions during matches in the English Football League were first permitted in the 1965-66 season. During the first two seasons after the law was introduced, each side was permitted only one substitution during a game. Moreover the substitute could only replace an injured player. From the 1967-68 season, this rule was relaxed to allow substitutions for tactical reasons.
On 21 August 1965, Keith Peacock of Charlton Athletic became the first substitute used in the Football League when he replaced injured goalkeeper Mike Rose eleven minutes into their away match against Bolton Wanderers.
The first official substitute in a Scottish League match was Paul Conn for Queen's Park v. Albion Rovers in a Division 2 match on 24 August 1966. Previously, on 20 January 1917, a player called Morgan came on for the injured Morrison of Partick Thistle after 5 minutes against Rangers at Firhill, but this was an isolated case and the Scottish League did not authorise substitutes until 1966.
In latter years, the number of substitutes permitted in Football League matches has gradually increased, at present each team is permitted to name five or seven substitutes depending on the country and competition, of which a maximum of three may be used. In England, the Premier League increased the number to 5 in 1996, and it was announced that the number available on the bench would be 7 for the 2008-09 season.
A player may only be substituted during a stoppage in play and with the permission of the referee. The player to be substituted (outgoing player) must have left the field of play before the substitute (incoming player) may enter the field of play; at that point the substitute becomes a player and the person substituted ceases to be a player. The incoming player may only enter the field at the half-way line. Failure to comply with these provisions may be punished by a caution (yellow card).
A player who has been substituted may take no further part in a match.
Both people nominated as substitutes though not yet used and players who have been substituted remain under the authority of the referee, and are liable for misconduct, though can not be said to have committed a foul.
Under the Laws, the referee has no specific power to force a player to be substituted, even if the team manager or captain has ordered their player to be substituted. If a player refuses to be substituted play may simply resume with that player on the field. However, in some situations players may still be liable to punishment with a caution (yellow card) for time wasting or unsporting behaviour.
A player who has been sent off (red card) may not be substituted; the team will have to make-do with the remaining players.
The term "super-sub" refers to a substitution made by the Coach (or Manager) that subsequently saves the game, e.g. by scoring a winning goal, or a player frequently used in this role, e.g. former Liverpool forward David Fairclough.