Squad number (association football)
Squad numbers are used in association football to identify and distinguish players that are on the field. Numbers very soon became a way to also indicate position, with starting players being assigned numbers 1–11, although 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.
Pelé during his tenure on the New York Cosmos wearing his iconic #10
First use of numbers in South America: Third Lanark and Argentine "Zona Norte" combined entering to the pitch with numbered jerseys, 10 June 1923
Arsenal FC wearing numbered shirts in a friendly v FC Vienna in 1933. Numbered shirts had first appeared in England in 1928 when Arsenal played Sheffield Wednesday. Their use would not be ruled mandatory until 1939
Lionel Messi displaying his squad number (10), as portrayed on his Argentina jersey in 2018
Goalkeeper (association football)
The goalkeeper is a position in association football. It is the most specialised position in the sport. The goalkeeper's main role is to stop the opposing team from scoring. This is accomplished by having the goalkeeper move into the trajectory of the ball to either catch it or direct it further from the vicinity of the goal line. Within the penalty area goalkeepers are allowed to use their hands, giving them the sole rights on the field to handle the ball. The goalkeeper is indicated by wearing a different coloured kit from their teammates and opposition.
Former Spain goalkeeper Iker Casillas – the first goalkeeper ever to keep one hundred international clean sheets (UEFA Euro 2012)
A goalkeeper (left, wearing a white shirt) being charged by a rival player (1905)
Maksym Koval (left) closes down Luis Suárez.
Goalkeeper Destin Onka Malonga (right) making a save