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.
The starters are commonly the best players on the team at their respective positions. Consequently, there is often a bit of prestige that is associated with being a starter. This is particularly true in sports with limited substitutions, like baseball or association football (soccer).
When listing a team's lineup, it is common in some sports to include each player's uniform number and their position, along with their name. Position are often designated by abbreviations that are specific to the sport (for example, in American football; "SS" for strong safety). In both baseball and basketball, it is common for a player's position to be denoted by a number, for example: in baseball scorekeeping the shortstop position is "6", while in basketball the small forward position is known as the "three". Thus, the lineups for some sports can include a uniform number, the player's name, and an abbreviation (consisting of letters or numbers) denoting a position.
In American football since the 1950s, most upper level teams use a three-platoon system, each with its own starting lineup. The starting lineups for offense and defense, each with eleven players, typically get the most attention. The starting lineups are defined as the eleven players who take the first offensive or defensive play from scrimmage of a given game. (An offensive player does not have to be on the team that gets possession first to be considered a starter, nor does a defensive player have to be on the team that does not; the first play from scrimmage after the first change of possession counts as well.) The third platoon, special teams, in modern times is composed mostly of backup and reserve players from the offensive or defensive platoons, with the exception of the placekicker or punter; the players who, for instance, take part in the opening kickoff are typically not considered starters.
The player positions dictate certain responsibilities and privileges in regard to handling the ball. A uniform numbering system restricts players' ability to change positions in the middle of the game.
The offensive lineup is heavily restricted by rules that have been adopted over the course of the game's development. Several positions (indicated with * in the list below) are mandatory and must appear in any lineup, starting or otherwise. Others can be used or unused at the discretion of a team's coach, provided that no more than 11 players are on the field at any given time and at least seven (usually exactly seven) are positions along the line of scrimmage.
In addition to the center, guards and tackles, at least two ends (be they tight ends or split end wide receivers) must also be in the lineup.
In recent history the 4-3 defense (4 defensive linemen plus 3 linebackers) formation has been standard among college and professional squads. However, the 3-4 (3 defensive linemen plus 4 linebackers) formation is becoming more popular among professional and NCAA Division I teams. Unlike offenses, defenses have no restrictions on positions (as long as no more than 11 players take the field), and the standard lineups have developed largely through tradition, experimentation, trial and error.
The third phase, special teams, generally designates only a few positions as "starters"; other than these specialists the other positions on the field are taken up as secondary positions by players who normally play offense or defense.
In association football, the starting lineup is termed a starting 11 (starting eleven) or starting XI. The starting 11 or starting XI is a list of the players who will actively participate in the game when the match begins.
The starting 11 consists of 11 players, with 1 designated goalkeeper. All other positions are optional, and teams can vary the player formations they use.
The formation are often described using the numbers of defenders, midfielders and forwards. For example, a commonly used formation is 4-4-2, which means there are 4 defenders, 4 midfielders and 2 strikers.  Some formations may list 4 numbers, which usually differentiates between defensive and attacking midfielders, e.g. 4-2-3-1 would mean 4 defenders, 2 defensive midfielders, 3 attacking midfielders, and 1 striker.
In Australian rules football, a team starts with eighteen players on the field. The traditional positions are as listed below, however in modern football the players are organised into three main groups, forwards, midfielders and defenders, each consisting of between four and eight players. Only four midfielders from each team are allowed to start inside the centre square, the other 14 players can start anywhere on the field.
The starting lineup in baseball comprises either nine or ten players. In the Central League of Nippon Professional Baseball, there are nine players in the starting lineup and all players bat. American League, National League (MLB) and Pacific League (NPB) teams have the option of using a designated hitter (DH) in place of the pitcher in the batting order. The DH does not play when the team is on defense.
In softball, where ten players are in the field, the tenth is usually placed in the outfield (OF); if placed between the infield and outfield, the extra fielder is known as a "rover."
The designated hitter (DH), when used, is designated with the number zero. In variants of the game where all nine positions plus a designated hitter must bat, the designated hitter is instead known as an extra hitter (EH).
In the National Basketball Association (NBA), two starting players are traditionally announced as guards, two as forwards, and one as a center. At least ten minutes before the game is scheduled to begin, the scorers need to be supplied with the name and number of each player who is to participate in the game.  The various positions are not mentioned anywhere in the official NBA rule book, and most players play more than one position.
The starting lineup on a basketball team usually comprises five positions and is called the 2-1-2 lineup (2 guards, 1 center, 2 forwards):
In American college basketball, a starting lineup is announced for each team before the game. Starting players are designated as either centers, forwards, or guards. A team can name at most one center, but otherwise any combination of positions is allowable, as long as five players are named. Lineups of three guards, one forward, and one center, or of three guards and two forwards, are the most common alternate lineups.
In Canadian football, a team starts with 12 players on offense, 12 players on defense, and a special teams squad of 12 players for punts, kickoffs, and extra point attempts. As in American football, most of the special teams players are starters or bench players for offence or defence.
Because of substantial differences between the two codes—most notably the larger field and only having three downs to advance the ball 10 yards instead of four—offensive formations are somewhat different in the Canadian game. Most notably, tight ends are almost completely absent in Canada.
The Canadian Football League has an additional rule that at least seven of the 24 offensive and defensive starters in a game be Canadian citizens. These seven starters can be of any position except quarterback.
Defences are broadly similar to those in American football, with an extra player used as a defensive back. Since most of the positions are essentially identical to those in American football, only the main differences will be listed here.
Positions generally similar to those in American football.
Gaelic football and hurling, as well as ladies' Gaelic football and camogie, use the same starting lineup.  Teams consist of one goalkeeper and fourteen outfield players (underage teams may play 13-a-side, omitting the full back and full forward positions). Teams lineup in six lines, with the goalkeeper furthest back and the full-forward line closest to the opposing team's goal. Players play on the left or right of the field looking in the direction they are attacking. Position numbering is fixed and positions are set up so that every attacker has a corresponding defender: for example, a right corner forward (jersey number 13) will be marked by a left corner back (4). Players sometimes swap positions during a match and there are sometimes tactical variations in formation, such as dropping one of the six forwards back to provide a third midfielder. Up to five substitutions are allowed during normal time (and another three if there is extra time), from a bench of 9 or sometimes 11 substitutions; substitutions are not numbered in any particular order.
In ice hockey, a team starts out with six players on the ice:
The starting forwards are typically known as the top line or first line, as most professional teams rotate four distinct three-man forward lines and three defense pairings.
In ice hockey, a team must submit their starting lineup to the opposing team's captain and to the officials before the game. If a team inserts any other player into the lineup at game time, the opposing captain can direct the official to call a starting the wrong lineup penalty, a two-minute minor.
The starting lineup in field lacrosse comprises ten players: 3 Attackmen, 3 Defensemen, 3 Midfielders, and 1 Goalkeeper. A team may start a Long-Stick Midfielder for a defensive advantage. A team may have a player reserved exclusively to take face-offs, known as a FOGO.
In netball, a team starts with seven players on the court:
A Rugby league football starting lineup is
Rugby union starting lineups consist of:
The starting lineup for a volleyball match typically includes:
Variations do exist – sometimes there will be two setters, or three outside hitters without a true opposite. Though the libero is typically announced with the starting lineup, the libero is not considered to be part of it, as the libero will replace one of the above players (typically a middle blocker, as teams will want to split their middle blockers, with one beginning in the front row) before the first rally.
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.
A running back (RB) is a member of the offensive backfield in gridiron football. The primary roles of a running back are to receive handoffs from the quarterback to rush the ball, to line up as a receiver to catch the ball, and block. There are usually one or two running backs on the field for a given play, depending on the offensive formation. A running back may be a halfback, a wingback or a fullback. A running back will sometimes be called a "feature back" if he is the team's starting running back.
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.
A cornerback (CB) is a member of the defensive backfield or secondary in gridiron football. Cornerbacks cover receivers most of the time, but also blitz and defend against such offensive running plays as sweeps and reverses. They create turnovers through hard tackles, interceptions, and deflecting forward passes.
A wide receiver (WR), also referred to as a wideout, historically known as a split end (SE) or flanker (FL), is an eligible receiver in gridiron football. A key skill position of the offense, WR gets its name from the player being split out "wide", farthest away from the rest of the offensive formation.
The tight end (TE) is a position in American football, arena football, and Canadian football, on the offense. The tight end is often 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.
In sports, a utility player is one who can play several positions competently. Sports in which the term is often used include association football, American football, baseball, rugby union, rugby league, softball, ice hockey, and water polo.
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.
American football positions have slowly evolved over the history of the sport. From its origins in early rugby football to the modern game, the names and roles of various positions have changed greatly, some positions no longer exist, and others have been created to fill new roles.
The 46 defense is an American football defensive formation, an eight men in the box defense, with six players along the line of scrimmage. There are two players at linebacker depth playing linebacker technique, and then three defensive backs. The 46 defense was originally developed and popularized with the Chicago Bears by their defensive coordinator Buddy Ryan, who later became head coach of the Philadelphia Eagles and Arizona Cardinals.
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.
A trick play, also known as a gadget play, gimmick play or trickeration, is a play in gridiron football that uses deception and unorthodox tactics to fool the opposing team. A trick play is often risky, offering the potential for a large gain or a touchdown if it is successful, but with the chance of a significant loss of yards or a turnover if not. Trick plays are rarely used not only because of the riskiness, but also to maintain the element of surprise for when they are used.
A halfback (HB) is an offensive position in American football, whose duties involve lining up in the offensive backfield and carrying the ball on most rushing plays, i.e. a running back. When the principal ball carrier lines up deep in the backfield, and especially when that player is placed behind another player, as in the I formation, that player is instead referred to as a tailback.
In American football, the specific role that a player takes on the field is referred to as their "position". Under the modern rules of American football, both teams are allowed 11 players on the field at one time and have "unlimited free substitutions", meaning that they may change any number of players during any "dead ball" situation. This has resulted in the development of three task-specific "platoons" of players within any single team: the offense, the defense, and the so-called 'special teams'. Within these three separate "platoons", various positions exist depending on the jobs that the players are doing.
The flexbone formation is an offensive formation in American football that includes a quarterback, five offensive linemen, three running backs, and varying numbers of tight ends and wide receivers. The flexbone formation is a predominant turnover formation derived from the wishbone formation and it features a quarterback under center with a fullback lined up directly behind the quarterback. There are two smaller running backs called slotbacks aligned behind the line of scrimmage on each side of the offensive line. The slotbacks are sometimes incorrectly referred to as wingbacks. But in order to be a wingback, there must be a guard, tackle and tight end all on one side of the center on the line of scrimmage and then the wingback off the line of scrimmage.
The triple option is an American football play used to offer several ways to move the football forward on the field of play. The triple option is based on the option run, but uses three players who might run with the ball instead of the two used in a standard option run.
In American football, a play is a close-to-the-ground plan of action or strategy used to move the ball down the field. A play begins at either the snap from the center or at kickoff. Most commonly, plays occur at the snap during a down. These plays range from basic to very intricate. Football players keep a record of these plays in a playbook.
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.
In American football, a back is a player who plays off of the line of scrimmage. Historically, the term "back" was used to describe multiple positions on offense and defense, although more descriptive and specific position naming is now common. Thus, "back" can refer to positions including: