All players must wear numerals on their jerseys in accordance with Rule 5, Section 3, Article 3(c ) [specifying allowable colors and font-sizes], and such numerals must be by playing position as follows: Quarterbacks, punters and place kickers, 1-19 (and 10-19 for wide receivers if 80-89 are all otherwise assigned), running backs and defensive backs 20-49; centers, 50-59 (60-79 if 50-59 unavailable; offensive guards and tackles, 60-79; wide receivers and tight ends, 80-89; defensive lineman 60-79 (90-99 if 60-79 unavailable); and linebackers,50-59 (90-99 if 50-59 unavailable).
If a players changes his position during his playing career in the NFL and such change moves him out of a catagory stated above, he must be issued an appropiate new jersey number.
Any request for a numeral for a special position not specified above (e.g. H.back) must be made to the Commissioner.
During the preseason when playing rosters are larger, the League the will allow duplications and other temporary deviations from the numbering scheme specified above, but the rule must be adhered to for all players during the regular season and postseason. Clubs must make numerals available to adhere to the rule, even if it requires putting back into circulation a numeral that has been retired or withheld for other reasons. See 7-2-3 for reporting change of position.