Uniform numbers in American football are unusual compared to those in other sports. They are displayed in more locations on the uniform; they are universally worn on both the front and back of the jersey; and in many cases "TV numbers" are displayed on either the jersey sleeves. the shoulder pad, or occasionally on the helmets. The numbers on the front and back of the jersey also are very large, covering most of the jersey. More importantly, certain numbers may only be worn by players playing specific positions; thus, the jersey numbers assist the officials in determining possible rules infractions by players.
Under current rules in all three of the most prominent levels of American football (high school football, college football and professional football), all players must wear a number from 1 to 99, and no two players on the same team may wear the same number on the field at the same time. Players could formerly use the numbers 0 and 00, numbers that were phased out in the 1970s, and on two special occasions in the 1960s, placekickers wore the number 100. Those who wear numbers from 50 to 79 are, by rule, prohibited from catching or touching forward passes if their team is in possession of the ball and may not line up in a position that allows them to do so-, unless explicitly indicated to the referee during a tackle-eligible play. Other than this, the correspondence between jersey numbers and player positions is largely a matter of style, tradition and semantics.
The related sport of Canadian football follows a similar numbering scheme to that of American scholastic football, except that the ineligible numbers span only from 50 to 69 and that 0 and 00 are still available for use. (Historically, the Canadian numbering scheme made numbers 40 to 69 ineligible.)
The National Football League numbering system dates from a large scale change of their rules in 1973, subsequently amended in various minor ways. As of 2015, players are generally required to wear numbers within ranges based on their positions as shown in the following table.
|Number Range||QB||RB/FB||WR||TE / H||OL||DL||LB||DB||K / P||LS|
Exceptions to this system do exist, including during the National Football League preseason with associated larger team rosters. The numbers used relate to the player's primary position when they are first assigned a number. If they later change positions, they can keep their prior number, unless it conflicts with the eligible receiver rule; that is only players that change positions from an eligible position (such as receiver or back) to an ineligible position (such as an offensive lineman) are required to change numbers if they change position. Additionally, during a game a player may play out-of-position, but only after reporting in to the referees, who will announce to the stadium that a specific player number has reported in (for example "Number 61 has reported as an eligible receiver") to alert the opposing team, other officials, and the audience that a player is legally out-of-position.
Although the NFL does allow teams to retire jersey numbers, the league officially discourages the practice for fear of teams running out of numbers; the rule book requires teams to make available retired numbers for new players should they exhaust all available numbers at a particular position.
According to NCAA rule book, Rule 1 Section 4 Article 1 "strongly recommends" numbering as follows for offensive players:
Otherwise all players can be numbered 1–99; the NCAA makes no stipulation on defensive players. Two players may also share the same number though they may not play during the same down.
The two players, both placekickers, to wear 100 in NCAA history both did so as centennial celebrations in the 1960s with special dispensation from the NCAA: West Virginia's Chuck Kinder (not the writer of the same name), who did so in 1963 to commemorate the state of West Virginia's 100th anniversary, and Kansas' Bill Bell, who did so in 1969 to commemorate 100 years since the first organized college football contest.
On high school and other lower youth teams, jerseys with different number ranges are different sizes, and since many of these teams do not reorder jerseys every year, players are often assigned numbers based more on jerseys that fit them rather than specific position. Odessa Permian High School (of Friday Night Lights fame) plays in Texas, where NCAA rules are used; yet Permian's tradition is that quarterbacks will wear numbers in the 20s unlike most schools in college or high school.
Although previous editions of the National Federation of State High School Associations rule book indicated a recommended numbering system nearly identical to the NCAA's, later editions from approximately 2000 onward only indicate the bare minimum requirements: offensive linemen must be numbered from 50 to 79, while all other positions including backs and ends must wear numbers either from 1 to 49 or 80 to 99.
In gridiron football, not all players on offense are entitled to receive a forward pass. Only an eligible pass receiver may legally catch a forward pass, and only an eligible receiver may advance beyond the neutral zone if a forward pass crosses into the neutral zone. If the pass is received by a non-eligible receiver, it is "illegal touching". If an ineligible receiver is beyond the neutral zone when a forward pass crossing the neutral zone is thrown, a foul of "ineligible receiver downfield" is called. Each league has slightly different rules regarding who is considered an eligible receiver.
The quarterback, colloquially known as the "signal caller", is a position in gridiron football. Quarterbacks are members of the offensive team and line up directly behind the offensive line. In modern American football, the quarterback is usually considered the leader of the offensive team, and is often responsible for calling the play in the huddle. The quarterback also touches the ball on almost every offensive play, and is the offensive player that almost always throws forward passes. When the QB is tackled behind the line of scrimmage, it is called a sack.
In gridiron football, a lineman is a player who specializes in play at the line of scrimmage. The linemen of the team currently in possession of the ball are the offensive line, while linemen on the opposing team are the defensive line. A number of NFL rules specifically address restrictions and requirements for the offensive line, whose job is to help protect the quarterback from getting sacked for a loss, or worse, fumbling. The defensive line is covered by the same rules that apply to all defensive players. Linemen are usually the largest players on the field in both height and weight, since their positions usually require less running and more strength than skill positions.
The tight end (TE) is a position in American football, arena football, and formerly Canadian football, on the offense. The tight end is often seen as a hybrid position with the characteristics and roles of both an offensive lineman and a wide receiver. Like offensive linemen, they are usually lined up on the offensive line and are large enough to be effective blockers. On the other hand, unlike offensive linemen, they are eligible receivers adept enough to warrant a defense's attention when running pass patterns.
Placekicker, or simply kicker, is the player in gridiron football who is responsible for the kicking duties of field goals and extra points. In many cases, the placekicker also serves as the team's kickoff specialist or punter as well.
Strategy forms a major part of American football. Both teams plan many aspects of their plays (offense) and response to plays (defense), such as what formations they take, who they put on the field, and the roles and instructions each player are given. Throughout a game, each team adapts to the other's apparent strengths and weaknesses, trying various approaches to outmaneuver or overpower their opponent in order to win the game.
Game play in American football consists of a series of downs, individual plays of short duration, outside of which the ball is dead or not in play. These can be plays from scrimmage – passes, runs, punts, or field goal attempts – or free kicks such as kickoffs and fair catch kicks. Substitutions can be made between downs, which allows for a great deal of specialization as coaches choose the players best suited for each particular situation. During a play, each team should have no more than 11 players on the field, and each of them has specific tasks assigned for that specific play.
A formation in football refers to the position players line up in before the start of a down. There are both offensive and defensive formations and there are many formations in both categories. Sometimes, formations are referred to as packages.
In sports, a starting lineup is an official list of the set of players who will participate in the event when the game begins. The players in the starting lineup are commonly referred to as starters, whereas the others are substitutes or bench players.
In gridiron football, a guard (G) is a player who lines up between the center and the tackles on the offensive line of a football team on the line of scrimmage used primarily for blocking. Right guards (RG) is the term for the guards on the right of the offensive line, while left guards (LG) are on the left side. Guards are to the right or left of the center.
In football, the tackle-eligible play is a forward-pass play in which coaches will attempt to create mismatches against a defense by inserting an offensive tackle, into an offensive formation as an eligible receiver, usually as a tight end or as a fullback. This is done by changing the formation of the offensive line, via positioning two linemen on one side of the center and three linemen on the other.
In team sports, the number, often referred to as the uniform number, squad number, jersey number, shirt number, sweater number, or similar is the number worn on a player's uniform, to identify and distinguish each player from others wearing the same or similar uniforms. The number is typically displayed on the rear of the jersey, often accompanied by the surname. Sometimes it is also displayed on the front and/or sleeves, or on the player's shorts or headgear. It is used to identify the player to officials, other players, official scorers, and spectators; in some sports, it is also indicative of the player's position.
In American football each team has 11 players on the field at one time. The specific role that a player takes on the field is called their position. Under the modern rules of American football, teams are allowed free substitutions; that is, teams may change any number of players after any play. This has resulted in the development of three "platoons" of players: the offense, the defense, and the special teams. Within those platoons, various specific positions exist depending on what each player's main job is.
The A-11 offense is an offensive scheme that has been used in some levels of amateur American football. In this offense, a loophole in the rules governing kicking formations is used to disguise which offensive players would be eligible to receive a pass for any given play. It was designed by Kurt Bryan and Steve Humphries of Piedmont High School in California.
The following terms are used in American football, both conventional and indoor. Some of these terms are also in use in Canadian football; for a list of terms unique to that code, see Glossary of Canadian football.
American football, referred to as football in the United States and Canada and also known as gridiron, is a team sport played by two teams of eleven players on a rectangular field with goalposts at each end. The offense, the team with possession of the oval-shaped football, attempts to advance down the field by running with the ball or passing it, while the defense, the team without possession of the ball, aims to stop the offense's advance and to take control of the ball for themselves. The offense must advance at least ten yards in four downs or plays; if they fail, they turn over the football to the defense, but if they succeed, they are given a new set of four downs to continue the drive. Points are scored primarily by advancing the ball into the opposing team's end zone for a touchdown or kicking the ball through the opponent's goalposts for a field goal. The team with the most points at the end of a game wins.
The Gene Upshaw Award is awarded to the best lineman, offensive or defensive, in NCAA Division II college football. The award is presented by the Manheim Touchdown Club and is recognized by the National Collegiate Athletic Association.
In gridiron football, an ineligible receiver downfield, or an ineligible man downfield, is a penalty called against the offensive team when a forward pass is thrown while a player who is ineligible to receive a pass is beyond the line of scrimmage without blocking an opponent at the time of the pass. A player is determined ineligible based on his position at the time of the snap. When the ball is snapped, the offense is required to have no more than eleven players on the field, out of whom only six are eligible. On most plays, the eligible receivers include the quarterback, running backs, fullbacks, tight ends, and wide receivers, while the ineligible receivers are offensive linemen, including the center, offensive guards, and offensive tackles.
Players in the National Football League wear uniform numbers between 1 and 99, and no two players on a team may wear the same number. Rules exist which tie a player's number to a specific range of numbers for their primary position. Additionally, rules exist which limit who may handle the ball on offense: generally players who are designated as offensive lineman, who wear numbers 50-79, are not allowed to handle the ball during a play from scrimmage, though they are allowed to do so if they report to the referee as playing out of position for a tackle-eligible play.