linebacker

members of the defensive team who line up approximately three to four yards behind the line of scrimmage, behind the defensive linemen; linebackers generally align themselves before the ball is snapped by standing upright in a two point stance; the number of linebackers is dependent upon the formation called for in the play; formations can call for as few as none, or as many as seven; most defensive schemes call for three or four, and they are named for the number of linemen, followed by the number of linebackers; for example, the 4-3 defense has four defensive linemen and three linebackers; conversely, the 3-4 defense has three linemen and four linebackers; linebackers must often be the most versatile players on the defensive team; they are called on to perform all functions of a defense from run support to pass rush to coverage.