Uniform numbers in the NFL are typically reserved based on player positions, with quarterbacks, kickers, and punters wearing numbers 1-9 and 10-19, running backs and defensive backs 20-49, centers and offensive linemen 50-79, wide receivers 10-19 and 80-89, tight ends 40-49 and 80-89, defensive linemen 60-99, and linebackers 40-59 and 90-99. The NFL season begins in August and runs through December playoffs and Super Bowl in February, with the draft held in April.