Linebacker (American football)

A linebacker (LB or backer) is a playing position in American football and Canadian football. Linebackers are members of the defensive team, and line up approximately three to five yards (4 m) behind the line of scrimmage, behind the defensive linemen, and therefore "back up the line." Linebackers generally align themselves before the ball is snapped by standing upright in a "two point stance" (as opposed to the defensive linemen, who put one or two hands on the ground for a "three point stance" or "four point stance" before the ball is snapped).

The goal of the linebacker is to provide either extra run protection or extra pass protection based on the particular defensive play being executed. Another key play of the linebacker position is blitzing. A blitz occurs when a linebacker acts as an extra pass rusher running into any exposed gap. When a blitz is called by the defense, it is mainly to sack or hurry the opposing offense's quarterback.

Linebackers are often regarded as the most important position in defence, due to their versatility in providing hard hits on running plays or an additional layer of pass protection, when required. Similar to the "free safety" position, linebackers are required to use their judgment on every snap, in order to determine their role during that particular play.

Before the advent of the two platoon system with separate units for offense and defense, the player who was the team's center on offense was often, though not always, the team's linebacker on defense. Hence today one usually sees four defensive linemen to the offense's five or more. Most sources claim coach Fielding H. Yost and center Germany Schulz of the University of Michigan invented the position. Schulz was Yost's first linebacker in 1904 when he stood up from his usual position on the line. Yost was horrified at first, but came to see the wisdom in Schulz's innovation.William Dunn of Penn St. was another Western linebacker soon after Schulz.

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