Linebacker (LB) is a playing position in gridiron football. Linebackers are members of the defensive team, and line up three to five yards behind the line of scrimmage and the defensive linemen. They are the "middle ground" of defenders, playing closer to the line of scrimmage than the defensive backs (secondary), but farther back than the defensive linemen.
As such, linebackers play a hybrid role and are often the most versatile players on the defensive side of the ball; they can be asked to play roles similar to either a defensive lineman (such as stopping the runner on a running play) or a defensive back (such as dropping back into pass coverage). How linebackers play their positions depends on the defensive alignment, the philosophy of the coaching staff, and the particular play the offense may call.
Linebackers are divided into middle linebackers, sometimes called inside linebackers, and outside linebackers. The middle linebacker, often called "Mike", is frequently the "quarterback of the defense". His central role on the field means he is in the best position to call defensive plays and direct shifts and changes based on what the offense is doing. Outside linebackers are often in a position to blitz, a defensive maneuver where the player rushes into the offensive backfield to disrupt a running play or sack the quarterback on passing plays. Besides "Mike", other nicknames such as "Sam", "Will", or "Jack", are commonly used to refer to various linebacking roles.
Historically, some of the most impactful defensive players, such as Pro Football Hall of Fame members Chuck Bednarik, Dick Butkus, Jack Lambert, Ray Lewis, Ray Nitschke, Mike Singletary, and Lawrence Taylor, were linebackers.
History
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, in contemporary football, 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 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 State was another Western Conference linebacker soon after Schulz.
However, there are various historical claims tied to the linebacker position, including some before 1904. For example, Percy Given of Georgetown is another center with a claim to the title "first linebacker," supposedly standing up behind the line well before Schulz in a game against Navy in 1902. Other sources have the first linebacker in the South as Frank Juhan, who played at Sewanee during 1908–1910.
In the East, Ernest Cozens of Penn was "one of the first of the roving centers," another archaic term for the position, supposedly coined by Hank Ketcham of Yale. Walter E. Bachman of Lafayette was said to be "the developer of the 'roving center' concept". Edgar Garbisch of Army was credited with developing the "roving center method" of playing defensive football in 1921.
In professional football, Cal Hubbard is credited with pioneering the linebacker position. He starred as a tackle and end, playing off the line in a style similar to that of a modern linebacker.