Football Player Numbers by Position

NFL Rule 5, Section 1, Article 4:

All players must wear numerals on their jerseys in accordance with Rule 5, Section 3, Article 3c (see NOTE 1), and such numerals must be by playing position as follows: quarterbacks, punters, and placekickers, 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).