In the past, when it was permitted to assign five substitute players in a match, the goalkeeper would also often wear the number 16, the last shirt number in the squad. Later on, when association football laws changed and it was permitted to assign seven substitute players, second-choice goalkeepers often wore the number 18. In the A-League, second-choice goalkeepers mostly wear number 20, based on that competition having a 20-man regulated "first team" squad size.