EventStays.com - About American Football
The Game - Offense & Defense
The Basics
A Football game consists of two teams - Offense and Defense. Each team has 11 players on the field at one time. There is no limit on substitutions.
The Offense is the team that has possession of the football and attempts to move down the field to score. Defense is the team that tries to prevent the other team from scoring. Both teams repeatedly have opportunities to score, on Offense, and to deny the opposing team from scoring, as Defense.
There are 4 ways to score points - a Touchdown (6 points), a Field Goal (3 points), a Safety (2 points), and the Extra Point(s) or Conversion (1-2 points; 1 point for a kick through the Goal Posts or 2 points for passing into the End Zone.)
A touchdown is when a player either runs the ball into the end zone or catches a pass in the end zone. The extra point is the play immediately after a team scores a touchdown. They get one chance to either kick the ball through the uprights or get the ball into the end zone via run or pass.
A field goal is when the ball is kicked through the goal posts (aka Uprights).
A safety is a bit out of the ordinary in so much as that it occurs when a player of the offensive team has the ball and gets tackled in their own end zone by a Defensive player. The 2 points goes to the Defensive team. Also, the Defensive team receives possession of the ball after the Safety by way of a Punt-like kick off.
A play typically begins when the Center snaps the ball to the Quarterback behind him. The Quaterback then will either hand the ball off to a runner or pass the ball to a receiver. There are other options as well, but that is what you will commonly see attempted. There are times when the Quarterback may choose to run the ball himself, take a knee (kneels down) which stops the play but keeps the game clock ticking, or spike the ball which stops the play and the game clock.
The Offense gets 4 "plays" (aka "downs") to either advance the ball at least 10 yards for a "1st" down, which is another set of 4 downs. This gets them closer to the end zone, where they can score, and gives them more plays (downs) to do so.
If the Offense has not advanced the ball 10 yards or has not scored by the 4th down, they have the option to Punt the ball. This means the Center snaps the ball to the Kicker, who then while holding the ball in his hand, kicks it down field to the receiving team who then become Offense during this transitional process.
If the Offense opts not to Punt the ball on 4th down, but instead decides to go for another 1st down (aka "go for it") and fails to get the 1st down or score, the opposing team then becomes the Offense and takes possession of the ball at that yard line (position on the field). If they had punted the ball, the opposing team would have taken possession much further down field and would have to work much harder to gain that yardage back and get into scoring position.
If and when the Offense scores, after they score, they will kick the ball to the other team. On a "Kick Off," the ball is kicked from the ground as opposed to from the kicker's hand. The Kick Off is another example of when the teams transition from Offense to Defense.
That's it in a nutshell. Below, take a look at the different Offensive Player Positions and what their roles are.
Offense Player Positions & Their Roles
Center (C) - the center performs the normal blocking functions of all linemen and is the player who puts the ball in play by means of the snap. On many teams the Center will be one of the "Team Captains" and depending on the amount of autonomy allowed by the team, some centers are responsible for coordinating and directing the efforts of the other members of the Offensive Line.
Offensive guard (OG) - the two guards are the offensive linemen directly on either side of the center and inside the tackles. Like all interior linemen, their function is to block on both running and passing plays. On some plays, rather than blocking straight ahead, a guard will "pull" - moving around behind the other offensive linemen upon the start of the play - in order to block a player on either side of the center, in an inside running play called a "trap" or an outside running play called a "sweep."
Offensive tackle (OT) - the offensive tackles play on the outer side of each guard. Their role is primarily to block on both running and passing plays. The area from one tackle to the other is an area of "close line play" in which blocks from behind, which are prohibited elsewhere on the field, are allowed. For a right-handed quarterback, the left tackle is charged with protecting the blindside, and is often faster than the other offensive linemen to stop 'speed rushers' at the Defensive End position. Like a guard, the tackle may have to "pull," on a running play, when there is a tight end on his side.
The description above of the guard and tackle positions apply only to a line that is balanced (has equal numbers of players on both sides of the player who is to snap the ball). In an unbalanced line, there may be players designated "guard" or "tackle" next to each other.
Offensive linemen cannot catch the ball but may run the ball if they want. In most circumstances, however, they do not. Except for the snap by the offensive center as each play from scrimmage starts, ordinarily the only way an offensive lineman can get the ball during a play is by picking up a fumble. On rare occasions offensive linemen legally catch passes; they can do so either by reporting as an eligible receiver to the referee prior to the snap or by catching a pass which has first been deflected or otherwise touched by an eligible receiver or a defensive player. Any other touching of a forward pass by an offensive lineman will result in a penalty.
Tight end (TE) - Tight ends play on either side of, and roughly next to, the tackles. They are a mix between a blocker and a pass receiver. If an end moves away from the tackle, he is called a split end. Modern formations typically have one tight end and one split end. Many modern formations also forego tight ends and replace them with wide receivers. Sometimes a formation is referred to as having "three tight ends." This means in reality that an additional blocker (a wingback or an eighth lineman) has been substituted for a wide receiver. This would be done as in short-yardage situations where receivers are not needed.
Wide receiver (WR) - The wide receivers are speedy pass-catching specialists. However, they can be bigger if they still can get open and catch the ball. Their main job is to run pass routes and get open for a pass, although they are occasionally called on to block. A wide receiver may line up on the line of scrimmage and be counted as one of the necessary seven players on the line in a legal formation (a split end), or he may line up at least one step behind the line of scrimmage and be counted as being in the backfield (a flanker if he is on the outside, a slot if he is not the outside receiver but is away from the tackle, or a wingback if he lines up near [usually adjacent to and just behind] the tackle). There are generally two types of wide receivers, "speed" and "possession." A speed receiver's primary function is to use his burst speed (speed from a standing start), to stretch the field (by forcing his coverage to retreat further into the back field in the hope that at the snap of the ball they [the pass coverage] will already be near where the receiver will catch the ball). The defense has to estimate where the speed receiver will move to; and may have to pull away an eight defensive man near the line of scrimmage who would otherwise move against the quarterback. A possession receiver is generally the more sure-handed of the two types and is used to keep possession of the ball by making catches that gain first down less yardage; but he usually lacks the speed to attack a defensive backfield. Passing long (deep into the backfield) to the possession receiver is a risk because equally quick or quicker defensive backs may be able to reach this receiver deep in their territory and (if they are so skilled), legally break up his reception of the ball. Also, if a pass is not properly thrown, is tipped, is carried by the wind (in an outdoor game), or the pass route is misunderstood between the passer and the receiver, the defense may use their equal or superior speed to make a clean interception of the ball.
Fullback (FB) - Positioned behind the middle of the line, a fullback may do some running, some blocking, and some short receiving. A classic fullback is more of a power runner than a running back. Many modern formations do not use a fullback. Most plays utilizing the fullback call for him to block, generally by running the planned rushing route behind the opening his offensive line has made in the opposite defensive lineup; and taking the block of the first linebacker(s) who tries to seal the gap the offensive line has made in the defense. By doing this the Fullback creates a path for the running back to run while having the ball. The greatest yardage can be gained by the running back when the fullback blocks, but concentrates on keeping on moving downfield with the running back advancing behind him. Should this blocking protection for the runner remain intact until the rushing convoy reaches the rear of the defensive secondary (the linebackers), and with the running back still on his feet and running downfield, one of the most memorable plays in the sport can be observed--that of an open-field run for long yardage or a touchdown.
(RB) - The modern term for the position formerly called "halfback" and often referred to as a "tailback." The running back carries the ball on most running plays and is also frequently used as a short-yardage receiver. Running backs, along with the wide receivers, are generally the fastest players on the offensive team. Most of them tend not to run straight ahead, preferring to make quick cutbacks to try to find holes in the defense. The running back is in fact looking for a clear path (of any shape) to the gap between the defensive secondary (the linebacker(s)) and the defensive backfield. A modern running back still on his feet in this gap can cross the distance down field before he can be tackled by the defensive secondary (he is usually much faster than they are). His small size, his speed, and his physical strength make it very difficult for defensive backs to catch him, or to legally bring him down if they do catch up to him on the run. The reason running backs are injury prone and rarely have long careers in the game is that either the initial hits they receive when the run directly into the defensive line; or when they are hit by the larger linebackers on the run do much damage to them, especially the knees and the ligaments (joints). "Fullback" is now regarded as a separate position from running back, with a substantially different role (especially in the NFL).
Quarterback (QB) - Typically the quarterback is positioned to take the football when the ball is snapped (handed or passed) between the center's legs. Recent usage refers imprecisely, however, to a player who is positioned behind the center at any distance, calls signals, is not the usual punter or place kick holder, and usually takes the snap as "quarterback" regardless of exact position, because those functions have typically been performed by quarterbacks. Typical play from formations where the quarterback takes the snap, will be followed by him either handing the ball off to a running back to run, throwing the ball downfield to a receiver, or running the ball down field himself.
Teams can vary the number of wide receivers, tight ends, and running backs on the field at one time. Football rules limit the flexibility of offensive formations. Seven players must line up on the line of scrimmage, and only the two at the end are eligible to catch passes. Sometimes, offensive lineman can declare eligibility and become "tackle eligible." Typical formations include:
One running back, two tight ends and two wide receivers.
Two running backs, one tight end and two wide receivers.
One running back, one tight end and three wide receivers.
One running back, no tight end and four wide receivers.
No running backs, no tight end and five wide receivers.
Defense is the team that begins a play from (the line of) scrimmage not in possession of the ball. The object of the defensive team is to prevent the other team from scoring. The sign that the defensive goal has been accomplished is recovering possession of the football before the offensive team scores, which usually involves the offensive team punting the ball on fourth down. Other possibilities include having the ball turned over on downs, getting an interception, or recovering a fumble. Also, if an offense advances down-field and into the red zone (within the 20-yard line of the defended end zone) and is threatening to score a touchdown, the defense can consider its goal accomplished if it forces the offense to settle for a field goal (three points) rather than a touchdown (six points).
Unlike the offensive team, there are no formally defined defensive positions from the perspective of the referee. A defensive player may line up anywhere on his side of the line of scrimmage and perform any legal action. Most sets used in football, however, include a line composed of defensive ends and defensive tackles and (behind the line) linebackers, cornerbacks, and safeties.
Defensive ends and tackles are collectively called defensive line, while the cornerbacks and safeties are collectively called the secondary, or defensive backs. Read below for more information on defensive player positions and their roles
Defensive Player Positions & Their Roles
Defensive end (DE) - The two defensive ends play on opposite outside edges of the defensive line. Their function is to attack the passer or stop offensive runs to the outer edges of the line of scrimmage (most often referred to as "containment"). The faster of the two is usually placed on the right side of the defensive line (quarterback's left) because that is a right-handed quarterback's blind side Defensive tackle (DT) - Sometimes called a defensive guard, defensive tackles are side-by-side linemen who are between the defensive ends. Their function is to rush the passer (if they can get past the offensive linemen blocking them), and stop running plays directed at the middle of the line of scrimmage. A defensive tackle who lines up directly across from the ball (and therefore is almost nose-to-nose with the offense's center) is often called a nose tackle or nose guard. The nose tackle is most common in the 3-4 defense and the quarter defense. Most defensive sets have from one to two defensive tackles. Sometimes, but not often, a team will employ three defensive tackles.
Nose guard (NG) - Sometimes called a middle guard, the nose guard lines up directly opposite the offensive center, or over the center's "nose." Nose guards tend to be shorter than most other defensive linemen. They are typically very strong and their responsibility is to stop runs down the middle and draw double teams. Extremely quick nose guards are sometimes used to shoot through the offensive line before it can react. They then sack the quarterback or make a tackle shortly after a hand off. This is rare, however, because most defensive linemen are not quick enough to consistently shoot the gaps between the individual offensive linemen. "Nose guard" is often a term incorrectly applied to the defensive tackle in a 3-4 defensive scheme. This position is known as a nose tackle. Nose guards are sometimes also referred to as middle guards.
Linebacker (LB) - Linebackers play behind the defensive line and perform various duties depending on the situation, including rushing the passer, covering receivers, and defending against the run. Most defensive sets have between two and three linebackers. Linebackers are usually divided into three types: strongside (left or right outside linebacker: LOLB or ROLB); middle (MLB); and weakside (LOLB or ROLB). The strongside linebacker usually lines up across from the offense's tight end; he is usually the strongest LB because he must be able to shed lead blockers quickly enough to tackle the running back. The middle linebacker mustcorrectly identify the offense's formations and what adjustments the entire defense must make. Because of this, the middle linebacker is nicknamed the "quarterback of the defense." The weakside linebacker is usually the most athletic or fastest linebacker because he usually must defend an open field.
Cornerback (CB) - Typically two players who primarily cover the wide receivers. Cornerbacks attempt to prevent successful quarterback passes by either swatting the airborne ball away from the receiver or by catching the pass themselves. In rushing situations, their job is to contain the rusher.
Safety (FS or SS) - The safeties are the last line of defense (farthest from the line of scrimmage) and usually help the corners with deep-pass coverage. The strong safety (SS) is usually the larger and stronger of the two, providing extra protection against run plays by standing somewhere between the free safety and the line of scrimmage. The free safety (FS) is usually the smaller and faster of the two, providing variable and extra pass coverage. Traditionally, teams have looked for safeties with reputations as hard hitters. More recently, however, teams have been looking for hybrid safeties who can do both jobs, as in a cover 2 defense, when the strong safety has a greater role to play in coverage. Safeties are also used in a variety of blitzes.
Defensive back (DB) - It is not a specific position; however, it is any position besides the line, including cornerbacks, safeties, etc., that is behind the line of scrimmage.
Nickelback and Dimeback - In certain formations, one extra (a fifth) defensive back (called a nickel defense), two extra (a sixth) DBs (called a Dime package), three extra (a seventh) DBs called a Quarter, or even four extra (an eighth) DBs called a Half Dollar may be used to augment the backfield or defensive line. (Keep in mind, an "extra" player means that they shift players away from one part of the Defensive field to another. There are never more than 11 players on the field for Defense.) Nickelbacks, Dimebacks, and Defensive Quarterbacks are usually used to defend pass plays with extra receivers, but they can also be used to rush quarterbacks or running backs more quickly than linemen or most linebackers can. A starting cornerback who is good at blitzing and tackling will sometimes be referred to as a Nickelback to distinguish them from cornerbacks.
Typical defensive formations include:

Five defensive linemen, two linebackers and four defensive backs (the 5-2 formation)
Five defensive linemen, three linebackers and three defensive backs (the 5-3 formation)
Four defensive linemen, three linebackers and four defensive backs (the 4-3 formation)
Four defensive linemen, four linebackers and three defensive backs (the 4-4 formation)
Three defensive linemen, four linebackers and four defensive backs (the 3-4 formation)
Three defensive linemen, three linebackers and five defensive backs (the 3-3-5 formation)
Four defensive linemen, two linebackers and five defensive backs (the Nickel formation)
Four defensive linemen, one linebacker and six defensive backs.(the Dime formation)
Three defensive linemen, one linebacker and seven defensive backs (the Quarter formation)
Three defensive linemen, no linebackers and eight defensive backs (the Half Dollar formation)
Special Teams
Special teams are units that are on the field during specific situations. They include a kickoff team, a kick return team, a punting team, a punt blocking and return team, a field goal and extra point team, a field goal blocking team and "hands team" used for onside kicks to prevent the kicking team from recovering a kick, usually by recovering the ball themselves. Though fewer points are scored on special teams than on offense, how special teams play determines where the offense will begin each drive, and thus it has a dramatic impact on how easy or difficult it is for the offense to score.
Because these aspects of the game can be so different from general offensive and defensive play, a specific group of players is drilled in executing them. Most special teams players are second- and third-string players from other positions, but there are also specialized players on these teams, including:
Kicker (K) - Handles kickoffs and field goal attempts, and in some leagues, punts as well.
Holder (H) - Usually positioned 7-8 yards from the line of scrimmage, he holds the ball for the placekicker to kick. The holder is often a backup quarterback or a punter.
Long snapper (LS) - A specialized center who snaps the ball directly to the holder or punter. All thirty-two NFL teams have specialized players just to long snap.
Kick returner (KR) - Returns kickoffs, generally is also a wide receiver or cornerback.
Punter (P) - Kicks punts. In leagues other than the NFL, the kicker often doubles as the punter.
Upback - A blocking back who lines up approximately 1-3 yards behind the line of scrimmage in punting and kneel situations. His primary job is to act as a second line of defense for the punter. Upbacks can receive a direct snap in fake punt situations.
Punt returner (PR) - Returns punts. Often the same player as the kick returner, although not necessarily so.
Gunner - A player on kickoffs and punts who specializes in running down the field very quickly in an attempt to tackle the kick returner or the punt returner.
Wedge Buster - A player whose goal is to sprint down the middle of the field on kickoffs. While ideally, their goal is to reach the kick returner, their immediate goal is to disrupt the wall of blockers (the wedge) on kickoffs, preventing the returner from having a lane in which to get a substantial return. Being a wedge buster is a very dangerous position since he may often be running at full speed when coming into contact with a blocker. This role has changed in the wake of the NFL largely banning wedges.