The quarterback (commonly abbreviated "QB"), colloquially known as the "signal caller", is a position in American and Canadian 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.
In modern American football, the quarterback is usually the leader of the offense, and their successes and failures can have a significant impact on the fortunes of his team.
The quarterback touches the ball on almost every offensive play.
Depending on the offensive scheme by his team, the quarterback's role can vary.
In the NFL, quarterbacks are required to wear a uniform number between 1 and 19. In the National Collegiate Athletic Association (NCAA) and National Federation of State High School Associations (NFHS), quarterbacks are required to wear a uniform number between 1 and 49; in the NFHS, the quarterback can also wear a number between 80 and 89. In the CFL, the quarterback can wear any number from 0 to 49 and 70 to 99. Because of their numbering, quarterbacks are eligible receivers in the NCAA, NFHS, and CFL; in the NFL, quarterbacks are eligible receivers if they are not lined up directly under center.
Often compared to captains of other team sports, before the implementation of NFL team captains in 2007, the starting quarterback is usually the de facto team leader and well-respected player on and off the field. Since 2007, when the NFL allowed teams to designate several captains to serve as on-field leaders, the starting quarterback has usually been one of the team captains as the leader of the team's offense.
In the NFL, while the starting quarterback has no other responsibility or authority, he may, depending on the league or individual team, have various informal duties, such as participation in pre-game ceremonies, the coin toss, or other events outside the game. For instance the starting quarterback is the first player (and third person after the team owner and head coach) to be presented with the Lamar Hunt Trophy/George Halas Trophy (after winning the AFC/NFC Conference title) and the Vince Lombardi Trophy (after a Super Bowl victory). The starting quarterback of the victorious Super Bowl team is often chosen for the "I'm going to Disney World!" campaign (which includes a trip to Walt Disney World for them and their families), whether they are the Super Bowl MVP or not; examples include Joe Montana (XXIII), Trent Dilfer (XXXV), Peyton Manning (50), Tom Brady and Julian Edelman (LIII). Dilfer was chosen even though teammate Ray Lewis was the MVP of Super Bowl XXXV, due to the bad publicity from Lewis' murder trial the prior year.
Being able to rely on a quarterback is vital to team morale. San Diego Chargers safety Rodney Harrison called the 1998 season a "nightmare" because of poor play by Ryan Leaf and Craig Whelihan and, from the rookie Leaf, obnoxious behavior toward teammates. Although their 1999 season replacements Jim Harbaugh and Erik Kramer were not stars, linebacker Junior Seau said "you can't imagine the security we feel as teammates knowing we have two quarterbacks who have performed in this league and know how to handle themselves as players and as leaders".
Commentators have noted the "disproportionate importance" of the quarterback, describing it as the "most glorified -- and scrutinized -- position" in team sports.
On a team's defense, the middle linebacker is regarded as "quarterback of the defense" and is often the defensive leader, since he must be as smart as he is athletic.
Compared to other positions in gridiron football, the backup quarterback gets considerably much less playing time than the starting quarterback.
A quarterback controversy results when a team has two capable quarterbacks competing for the starting position.
Trends and other roles
In addition to their main role, quarterbacks are occasionally used in other roles.
As Roger Staubach's back-up, Dallas Cowboys quarterback Danny White was also the team's punter, opening strategic possibilities for coach Tom Landry. Ascending the starting role upon Staubach's retirement, White held his position as the team's punter for several seasons—a double duty he performed to All-American standard at Arizona State University. White also had two touchdown receptions as a Dallas Cowboy, both from the halfback option.
If quarterbacks are uncomfortable with the formation the defense is using, they may call an audible change to their play.
Quarterbacks can also "spike" (throw the football at the ground) to stop the official game clock. For example, if a team is down by a field goal with only seconds remaining, a quarterback may spike the ball to prevent the game clock from running out. This usually allows the field goal unit to come onto the field, or attempt a final "Hail Mary pass". However, if a team is winning, a quarterback can keep the clock running by kneeling after the snap. This is normally done when the opposing team has no timeouts and there is little time left in the game, as it allows a team to burn up the remaining time on the clock without risking a turnover or injury.
A dual-threat quarterback possesses the skills and physique to run with the ball if necessary. With the rise of several blitz-heavy defensive schemes and increasingly faster defensive players, the importance of a mobile quarterback has been redefined.
Dual-threat quarterbacks have historically been more prolific at the college level.
Some teams employ a strategy which involves the use of more than one quarterback during the course of a game.
There are four circumstances in which a two-quarterback system may be used.
The first is when a team is in the process of determining which quarterback will eventually be the starter, and may choose to use each quarterback for part of the game in order to compare the performances.
The second is a starter–reliever system, in which the starting quarterback splits the regular season playing time with the backup quarterback, although the former will start playoff games.
The third is if a coach decides that the team has two quarterbacks who are equally effective and proceeds to rotate the quarterbacks at predetermined intervals, such as after each quarter or after each series.
The fourth, still occasionally seen in major-college football, is the use of different quarterbacks in different game or down/distance situations.
The quarterback position dates to the late 1800s, when American Ivy League schools playing a form of rugby union imported from the United Kingdom began to put their own spin on the game. Walter Camp, a prominent athlete and rugby player at Yale University, pushed through a change in rules at a meeting in 1880 that established a line of scrimmage and allowed for the football to be snapped to a quarterback. The change was meant to allow for teams to strategize their play more thoroughly and retain possession more easily than was possible in the chaos of a scrummage in rugby. In Camp's formulation, the "quarter-back" was the person who received a ball snapped back with another player's foot. Originally he was not allowed to run forward of the line of scrimmage:
The quarterback in this context was often called the "blocking back" as their duties usually involved blocking after the initial handoff. The "fullback" was the furthest back behind the line of scrimmage. The "halfback" was halfway between the fullback and the line of scrimmage, and the "quarter-back" was halfway between the halfback and the line of scrimmage. Hence, he was called a "quarter-back" by Walter Camp.
The requirement to stay behind the line of scrimmage was soon rescinded, but it was later re-imposed in six-man football. The exchange between the person snapping the ball (typically the center) and the quarterback was initially an awkward one because it involved a kick. At first, centers gave the ball a small boot, and then picked it up and handed it to the quarterback. By 1889, Yale center Bert Hanson was bouncing the ball on the ground to the quarterback between his legs. The following year, a rule change officially made snapping the ball using the hands between the legs legal. Several years later, Amos Alonzo Stagg at the University of Chicago invented the lift-up snap: the center passed the ball off the ground and between his legs to a standing quarterback. A similar set of changes were later adopted in Canadian football as part of the Burnside rules, a set of rules proposed by John Meldrum "Thrift" Burnside, the captain of the University of Toronto's football team.
The change from a scrummage to a "scrimmage" made it easier for teams to decide what plays they would run before the snap. At first, the captains of college teams were put in charge of play-calling, indicating with shouted codes which players would run with the ball and how the men on the line were supposed to block. Yale later used visual signals, including adjustments of the captain's knit hat, to call plays. Centers could also signal plays based on the alignment of the ball before the snap. In 1888, however, Princeton University began to have its quarterback call plays using number signals. That system caught on, and quarterbacks began to act as directors and organizers of offensive play.
Early on, quarterbacks were used in a variety of formations.
In 1906, the forward pass was legalized in American football; Canadian football did not adopt the forward pass until 1929. Despite the legalization of the forward pass, the most popular formations of the early 20th century focused mostly on the rushing game.
Offensive play-calling continued to focus on rushing up through the 1920s, when professional leagues began to challenge the popularity of college football. In the early days of the professional National Football League (NFL), which was founded in 1920, games were largely low-scoring affairs. Two-thirds of all games in the 1920s were shutouts, and quarterbacks/tailbacks usually passed only out of desperation. In addition to a reluctance to risk turnovers by passing, various rules existed that limited the effectiveness of the forward pass: passers were required to drop back five yards behind the line of scrimmage before they could attempt a pass, and incomplete passes in the end zone resulted in a change of possession and a touchback. Additionally, the rules required the ball to be snapped from the location on the field where it was ruled dead; if a play ended with a player going out of bounds, the center had to snap the ball from the sideline, an awkward place to start a play.
Despite these constraints, player-coach Curly Lambeau of the Green Bay Packers, along with several other NFL figures of his era, was a consistent proponent of the forward pass. The Packers found success in the 1920s and 1930s using variations on the single-wing that emphasized the passing game. Packers quarterback Red Dunn and New York Giants and Brooklyn Dodgers quarterback Benny Friedman were the leading passers of their era, but passing remained a relative rarity among other teams; between 1920 and 1932, there were three times as many running plays as there were passing plays.
Early NFL quarterbacks typically were responsible for calling the team's offensive plays with signals before the snap. The use of the huddle to call plays originated with Stagg in 1896, but only began to be used regularly in college games in 1921. In the NFL, players were typically assigned numbers, as were the gaps between offensive linemen. One player, usually the quarterback, would call signals indicating which player was to run the ball and which gap he would run toward. Play-calling or any other kind of coaching from the sidelines was not permitted during this period, leaving the quarterback to devise the offensive strategy (often, the quarterback doubled as head coach during this era). Substitutions were limited, and quarterbacks often played on both offense and defense. 
The period between 1933 and 1945 was marked by numerous changes for the quarterback position. The rule requiring a quarterback/tailback to be five yards behind the line of scrimmage to pass was abolished. Hash marks were added to the field that established a limited zone between which the ball was placed before snaps, making offensive formations more flexible. Additionally, incomplete passes in the end zone were no longer counted as turnovers and touchbacks.
The single-wing continued to be in wide use throughout this, and a number of forward-passing tailbacks became stars, including Sammy Baugh of the Washington Redskins. In 1939, University of Chicago head football coach Clark Shaughnessy made modifications to the T-formation, a formation that put the quarterback behind the center and had him receive the snap directly. Shaughnessy altered the formation by having the linemen be spaced further apart, and he began having players go in motion behind the line of scrimmage before the snap to confuse defenses. These changes were picked up by Chicago Bears coach George Halas, a close friend of Shaughnessy, and they quickly caught on in the professional ranks. Utilizing the T-formation and led by quarterback Sid Luckman, the Bears reached the NFL championship game in 1940 and beat the Redskins by a score of 73–0. The blowout led other teams across the league to adopt variations on the T-formation, including the Philadelphia Eagles, Cleveland Rams and Detroit Lions. Baugh and the Redskins converted to the T-formation and continued to succeed.
Thanks in part to the emergence of the T-formation and changes in the rulebooks to liberalize the passing game, passing from the quarterback position became more common in the 1940s and as teams switched to the T-formation, passing tailbacks, such as Sammy Baugh, would line up as quarterbacks instead. Over the course of the decade, passing yards began to exceed rushing yards for the first time in the history of football. The Cleveland Browns of the late 1940s in the All-America Football Conference (AAFC), a professional league created to challenge the NFL, were one of the teams of that era that relied most on passing. Quarterback Otto Graham helped the Browns win four AAFC championships in the late 1940s in head coach Paul Brown's T-formation offense, which emphasized precision timing passes. Cleveland, along with several other AAFC teams, was absorbed by the NFL in 1950 after the dissolution of the AAFC that same year. By the end of the 1940s, all NFL teams aside from the Pittsburgh Steelers used the T-formation as their primary offensive formation.
As late as the 1960s, running plays occurred more frequently than passes.
The NFL continues to be a pass-heavy league, in part due to further rule changes that prescribed harsher penalties for hitting the quarterback and for hitting defenseless receivers as they awaited passes. Passing in wide-open offenses has also been an emphasis at the high school and college levels, and professional coaches have devised schemes to fit the talents of new generations of quarterbacks.
While quarterbacks and team captains usually called plays in football's early years, today coaches often decide which plays the offense will run.
Dallas Cowboys head coach Tom Landry was an early advocate of taking play calling out of the quarterback's hands. Although this remained a common practice in the NFL through the 1970s, fewer QBs were doing it by the 1980s and even Hall of Famers like Joe Montana did not call their own plays. Buffalo Bills QB Jim Kelly was one of the last to regularly call plays. Peyton Manning, formerly of the Indianapolis Colts and Denver Broncos, was the best modern example of a quarterback who called his own plays, primary using an uptempo, no-huddle-based attack. Manning had almost complete control over the offense. Former Baltimore Ravens quarterback Joe Flacco retained a high degree of control over the offense as well, particularly when running a no-huddle scheme, as does Ben Roethlisberger of the Pittsburgh Steelers.
During the 2013 season, 67 percent of NFL players were African American (blacks make up 13 percent of the US population), yet only 17 percent of quarterbacks were; 82 percent of quarterbacks were white, with just one percent of quarterbacks from other races. In 2017, the New York Giants benched longtime starter Eli Manning in favor of Geno Smith, who was declared the starter. The Giants were the last team to have never fielded a black starting QB during an NFL season.
Some black quarterbacks claim to have experienced bias towards or against them due to their race.