A defensive tackle (DT) is a position in American football that typically lines up on the line of scrimmage, opposite one of the offensive guards; however, he may also line up opposite one of the offensive tackles. Defensive tackles are typically the largest and strongest of the defensive players. Depending on a team's defensive scheme, a defensive tackle may be called upon to fill several different roles. These may include merely holding the point of attack by refusing to be moved, or penetrating a certain gap between offensive linemen to break up a play in the opponent's backfield. If a defensive tackle reads a pass play, his primary responsibility is to pursue the quarterback, or simply knock the pass down at the line if it is within arm's reach. Other responsibilities of the defensive tackle may be to pursue the screen pass or drop into coverage in a zone blitz scheme. In a traditional 4–3 defense, there is no nose tackle. Instead there are a left and a right defensive tackle. Some teams, especially in the National Football League (NFL), have a nose tackle in this scheme, but most of them do not.
Defensive tackle Pat Williams (in blue)
American football, also known as gridiron football, 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 throwing 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. A game is won by the team with the higher number of points, which 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.
Larry Fitzgerald (in blue) catches a pass while Cortland Finnegan (in red) plays defense at the 2009 Pro Bowl.
Walter Camp, the "Father of American Football", in 1878 when Camp was captain of Yale University's football team
The dangers associated with the sport depicted in a 1908 cartoon by William Charles Morris
Pudge Heffelfinger, widely regarded as the first professional football player