Association football clubs around the world sometimes retire squad numbers to recognise players' service to the club, whether that be through their loyalty or quality.
This practice, long established in the major North American sports, is a recent development in football elsewhere, since squad numbers for specific players were not widely used until the 1990s. Before then, it was typical for players in the starting lineup to be issued numbers 1 to 11 by formation/position on a match-by-match basis, and substitutes to be numbered from 12 upwards, meaning a player might wear different numbers during the season if they were to play in different positions for tactical reasons, or simply not be a regular in the starting lineup.
In contrast, in the former American league the North American Soccer League, players wore permanent numbers since its inception in 1967. Moreover, Pelé's #10 was retired by the New York Cosmos during the farewell of the Brazilian star on 1 October 1977, becoming the first number ever retired in association football.
Mexico was a pioneer country in the use of permanent numbers in football; these were adopted in the Primera División in the 1980s.
Retiring a player's shirt number usually occurs after the player has left the team or retired. It honours a player who has meant much to his club, and no other player is permitted to use that number in the future. In some cases, such as those of Marc-Vivien Foé, Davide Astori, and Diogo Jota, numbers have been retired to posthumously honour a player who died while still active. Also, Norwegian club Fredrikstad retired Dagfinn Enerly's number following an on-pitch accident that left him paralysed. In Britain, only Bobby Moore's, Jack Lester's, and Jude Bellingham's shirt numbers have been retired due to great service to the club as opposed to a tragic incident. Although it had not been officially retired, Gianfranco Zola's No. 25 shirt had not been reissued by Chelsea since he left the club in 2003 until re-issued to Moisés Caicedo in 2023.
The Argentina, Ecuador and Cameroon national teams have been prevented from retiring the numbers of Diego Maradona (10), Christian BenÃÂtez (11) and Marc-Vivien Foé (17), respectively, by FIFA rules dealing with squad numbers for Finals tournaments; in other competitions, qualifiers or friendlies, national associations may assign numbers according to criteria of their choosing. Similarly, several clubs have been required to reissue retired numbers for continental club competitions due to squad numbering rules of continental confederations. For example, CAF and CONMEBOL have such rules in their club competitions, but CONCACAF does not.
Some South American teams (such as Universitario de Deportes and Flamengo, and even Mexican teams invited for the occasions) occasionally had to re-issue their retired numbers for special cases due to CONMEBOL rules, which stated that shirts had to be numbered 1âÂÂ25/30 in continental club competitions (such as Copa Libertadores and Copa Sudamericana, among others), although nowadays clubs are not forced to number their players consecutively.
Some clubs dedicate a number to their fans, and do not issue it to any player. The most common number for this practice is 12, from descriptions of the fans as "the twelfth man". Clubs and teams that do not give the '12' to any player include: