Uniform number (American football)

In American football, uniform numbers are displayed on both the front and back of the jersey, and in many cases the sleeves, shoulder pad, or occasionally helmets.

Players who wear numbers from 50 to 79 are, by rule, prohibited from catching or touching forward passes if their team is in possession of the ball and may not line up in a position that allows them to do so, unless explicitly indicated to the referee during a tackle-eligible play.

Other than this, the correspondence between jersey numbers and player positions is largely a matter of style, tradition and semantics.

The National Football League numbering system dates from a large-scale change of their rules in 1973, subsequently amended in various minor ways.

[1] Exceptions to this system do exist, including during the National Football League preseason with associated larger team rosters.

Both did so as part of centennial celebrations in the 1960s, with special dispensation from the NCAA: West Virginia's Chuck Kinder (not the writer of the same name), who did so in 1963 to commemorate the state of West Virginia's 100th anniversary, and Kansas' Bill Bell, who did so in 1969 to commemorate 100 years since the first organized college football contest.