In American football, jammers try to slow down gunners during punts by preventing them from getting a free release, giving punt returners more time to return punts. A jammer is typically played by a back-up for another position. This position is usually referred to simply as a special teamer, or even a gunner.
|Positions in American football and Canadian football|
|Offense (Skill position)||Defense||Special teams|
|Linemen||Guard, Tackle, Center||Linemen||Tackle, End||Kicking players||Placekicker, Punter, Kickoff specialist|
|Quarterback (Dual-threat, Game manager, System)||Linebacker||Snapping||Long snapper, Holder|
|Backs||Halfback/Tailback (Triple-threat), Fullback, H-back, Wingback||Backs||Cornerback, Safety, Halfback, Nickelback, Dimeback||Returning||Punt returner, Kick returner, Jammer, Upman|
|Receivers||Wide receiver (Eligible), Tight end, Slotback, End||Tackling||Gunner, Upback, Utility|
|Formations (List) -- Nomenclature -- Strategy|