Below are some of the common player positions, the initials used to show where they play and what their role is on the team.
Quarterback:
(QB) The leader of the team, directs the offense. He calls the
plays in the huddle. He lines up directly behind the center, and
takes the snap from him. He can run, pass to a receiver or back,
or hand off to another runner.
Running Back: (RB) He carries the football, the main runner on the team. He can catch passes too. He lines up in the backfield behind the quarterback. Some teams call him a half back.
Full Back: (FB) A runner that usually blocks for the running back, and also can carry the ball. He can catch passes too. He lines up in the backfield behind the quarterback.
Tight End: (TE) A player that can go out for passes, and is called the tight end because he line up next to the tackle on the offensive line. Usually a good blocker.
Wide Receiver: (WR) He is the main pass catcher on offense. Called a wide receiver because he lines up wide of the other players on the offensive line. Sometime teams call him a flanker or give him a letter like X or Y. Most long pass plays are completed to wide receivers.
Tackle: (LT or RT) A lineman that blocks. There are two tackles on a line. They are the outside blockers. There is a left tackle and a right tackle.
Guard: (LG or RG) A lineman that blocks. There are two guards on a line. They line up inside of the tackles. Guards often pull or block on sweeps. There is a right guard and a left guard.
Center: (C) The player that snaps the ball. He is responsible for calling out blocking assignments. He lines up over the ball.
Defensive End: (DE) A lineman on defense who plays on the outside of the defensive line. These players are good pass rushers. There are usually two ends.
Defensive Tackle: (DT) A lineman that plays inside the ends and is good stopping the run. There are usually two tackles.
Nose Guard: (NG) Some teams use this player on defense to help stop the run. He lines up right in front of the center. He a nose guard because he is supposed to have a "nose" for the ball.
Linebacker: (LB) These players line up behind or in back of the defensive line. They are good at covering short passes, stopping the run, and blitzing. Some teams use three and some teams use four linebackers.
Middle Linebacker: (MLB) A linebacker who lines up in the middle or even with the ball.
Outside Linebacker: (OLB) A linebacker that plays on the outside of the defensive ends. These players like to blitz and can cover receivers well.
Safety: (S) A player who plays ten to fifteen yards off and even with the ball and helps cover the whole field. His main responsibility is not to let any player on offense get past him. He is call out the defensive backs signals.
Strong Safety: (SS) The player who watches the tight end. He can either play up close to the line or back further. He helps on deep passes. Some teams call him a free safety.
Cornerback: (CB) These players cover the wide receivers. They try to prevent passes being completed to receivers. Teams usually use two cornerbacks, one on each side of the field. In plays where the defensive thinks the offense must pass, teams add a third cornerback and call him a nickel back (NB) or even a fourth back and call him the dime back (DB).
Kicker: (K) A player that kicks off and kicks extra points and field goals.
Punter: (P) A player that kick the ball down filed to the other team on fourth down. Teams like to have a punter that kicks the ball high and far. This helps the defense.
Return Specialist: a player that returns kicks and punts. His job is to catch the ball and try to get as far as he can.