Squad number (association football)

Squad numbers are used in association football to identify and distinguish players who are on the field. Numbers very soon became a way to also indicate position, with starting players being assigned numbers 1–11. However, there is no fixed rule; numbers may be assigned to indicate position, alphabetically by name, according to a player's whim, randomly, or in any other way. In the modern game they are often influenced by the players' favourite numbers and other less technical reasons, as well as using "surrogates" for a number that is already in use. However, numbers 1–11 are often still worn by players of the previously associated position.

As national leagues adopted squad numbers and game tactics evolved over the decades, numbering systems evolved separately in each football scene, and so different countries have different conventions. Still, there are some numbers that are universally agreed upon being used for a particular position, because they are quintessentially associated with that role.

For instance, "1" is frequently used by the starting goalkeeper, as the goalkeeper is the first player in a line-up. "9" is usually worn by strikers, also known as centre-forwards, who hold the most advanced offensive position on the pitch, and are often the highest scorers in the team. "10" is one of the most emblematic squad numbers in football, due to the sheer number of football legends that have worn the number 10 shirt; playmakers, second strikers, and attacking midfielders have worn this number.

The first record of numbered jerseys in football date back to 1911, with Australian teams Sydney Leichardt and HMS Powerful being the first to use squad numbers on their backs. One year later, numbering in football would be ruled as mandatory in New South Wales.

The next recorded use was on 23 March 1914 when the English Wanderers, a team of amateur players from Football League clubs, played Corinthians at Stamford Bridge, London. This was Corinthians' first match after their FA ban for joining the Amateur Football Association was rescinded. Wanderers won 4–2.

In South America, Argentina was the first country with numbered shirts. It was during the Scottish team Third Lanark tour to South America of 1923, they played a friendly match v a local combined team ("Zona Norte") on 10 June. Both squads were numbered from 1–11.

On 30 March 1924, saw the first football match in the United States with squad numbers, when the Fall River F.C. played St. Louis Vesper Buick during the 1923–24 National Challenge Cup, although only the local team wore numbered shirts.

The next recorded use in association football in Europe was on 25 August 1928 when The Wednesday played Arsenal and Chelsea hosted Swansea Town at Stamford Bridge. Numbers were assigned by field location: