The
National Football League numbering system dates from a large-scale rules change in 1973, subsequently amended in various minor ways. As of 2023, players are generally required to wear numbers within ranges based on their positions as shown in the following table. Exceptions to this system do exist, including during the
National Football League preseason with associated larger team rosters. The numbers used relate to the player's primary position when he is first assigned a number. If he later changes positions, he can keep his prior number, unless it conflicts with the eligible receiver rule; that is, only players who change positions from an eligible position (such as receiver or back) to an ineligible position (such as an offensive lineman) are required to change numbers if they change position. Additionally, during a game a player may play out-of-position, but only after reporting in to the referees, who will announce to the stadium that a specific player number has reported in (for example "Number 61 has reported as an eligible receiver") to alert the opposing team, other officials, and the audience that a player is legally out-of-position. Although the NFL does allow teams to
retire jersey numbers, the league officially discourages the practice for fear of teams running out of numbers; the rule book requires teams to make available retired numbers for new players should they exhaust all available numbers at a particular position. The NFL rulebook does not specify an official jersey number range for long snappers. However, they typically wear numbers between 40 and 59, with occasional exceptions. In the
XFL, the NFL numbering conventions were followed with a slight exception being that wide receivers are allowed to wear single-digit numbers (i.e. 1–9); the NFL itself added that allowance starting in 2021. ==NCAA==