Association football clubs around the world sometimes retire squad numbers to recognise players' loyal service, most as a memorial after their death. Background 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 American league NASL, players have always worn 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, probably 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 Jason Mayélé, Vittorio Mero, Marc-Vivien Foé, Miklós Fehér, Ray Jones, Dylan Tombides, François Sterchele, David di Tommaso, Antonio Puerta, Besian Idrizaj, Piermario Morosini and Davide Astori, 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 has not been officially retired, Gianfranco Zola's No. 25 shirt has not been reissued by Chelsea since he left the club in 2003. The Argentina, Ecuador and Cameroon national teams have been prevented from retiring the numbers of Diego Maradona (10), Christian Benítez (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