linebacker

A linebacker is a defensive player in American football who lines up behind the defensive line and in front of the secondary. Linebackers are responsible for stopping the run, defending against the pass, and sometimes rushing the quarterback. They must read the offense and react quickly, acting as a versatile second level of the defense.

Linebackers are commonly classified as middle linebackers (Mike) and outside linebackers (Will and Sam). In a 4-3 defense, three linebackers typically line up behind the linemen: the middle linebacker and two outside linebackers. In a 3-4 defense, there are four linebackers—usually two inside and two outside—that often play dual roles as run stoppers and pass rushers. The middle linebacker frequently acts as the defensive signal-caller on many teams.

Key attributes include size, speed, tackling ability, and football intelligence. Linebackers read formations, diagnose plays, and fill gaps to stop the run. In pass defense, they may cover running backs or tight ends in zone or man coverage, drop into underneath zones, or blitz the quarterback. Some linebackers specialize as edge rushers or hybrids who contribute in multiple phases of defense.

Modern offenses require linebackers to be versatile, capable of speed and coverage as well as run support. Teams use nickel and dime packages that reduce traditional linebackers or place lighter, faster players on the field. The position has a long history; its roles have evolved with changes in formations and passing games, but linebackers remain central to defensive schemes.