In American Football, only 11 players from each team are on the field at any given moment, although a full team of players totals 45. Under the modern rules of the game, a team may make any number of substitutions that it wishes, but this can only be done at the end of a play.
The result of this has been that teams have formed into three different “platoons” one of which will be on the field at any time depending on the role that is required. The three platoons are the Offense, which is the team with the ball endeavoring to score, the Defense which is trying to stop the offense from scoring, and the Special Team which is fielded when there is kicking play.
The Offense is the team in possession of the ball and its’ job is to reach the end zone of the opposing team (the Defense) and score a touchdown.
Different teams will use variations on a theme, but for the purposes of this article we will use a fairly standard illustration.
Of the eleven players on the field, eight of them are formed into a T shape. Five players will form a line across the 50 yard scrimmage line, with three players behind them one behind the other forming the trunk of the “T”. The player in the center of the five is, as might be guessed, the Center. On his left and right are two Guards, and outside the Guards are two Tackles. Standing behind the Center around the middle of the 40 yard line is the Quarterback, and behind him is a full back/running back, with another full back/running back at the rear.
At one side or other of the two Tackles is a Tight End, and at the outside of the field on the same line are two Wide Receivers, one on each side.
Broadly speaking, the five offensive linemen (Center, Guards, and Tackles) have a main job which is to block, while the other six players have the job of pressing forward with the ball either by running with it or by passing it to one of the other “eligible” players, i.e. Wide Receivers, Tight End, Quarterback, or Full Backs/Running Backs. Offensive linemen are not eligible to press forward with the ball past the line of scrimmage.
The Center begins the play by “snapping” the ball between his legs back to the Quarterback. The two Guards are there to block the defensive players from getting at the player with the ball, while the two Tackles perform a similar role. Tackles are usually tall men (very often over 6’4”) and heavily built.
Once the Quarterback has the ball he has the option of running with it, passing it to another eligible player, or may forward pass it to a player who has run downfield. The Quarterback is also in charge of receiving instructions from the coaches on the side line, and communicating them to the other players in the “huddle”.
The rules of football do not restrict the defensive players from any sort of activity, and they can line up anywhere on their side of the scrimmage line and perform any legal maneuver.
By and large, the Defensive linemen line up close to the Offensive linemen head to head. In the center is the Defensive Tackle whose job is to rush the offensive passer, assuming he can get past the other team’s linemen. There may be two Defensive Tackles. Outside these are Defensive Ends who also try to rush the passer, and block offensive runs on the outer edge of the scrimmage line.
Defensive Backs play behind the Linebackers and are literally the last line of defense against the offensive side.
These are players who perform kicking roles, which may be kick-offs, field goal, or extra points attempts. There are also Holders who specialize in holding the ball for the placekicker to kick, and a variety of other specialists such as Punters, Punt Returners, Upbacks, Gunners, Jammers, and more.
American Football positions can consist of players who, although given a specific name, may perform many different tasks on the field depending on the way the game is going, the way the opposition performs, and instructions from the coaches. It is a tough sport, and certainly not for the faint-hearted.