Linebackers are key defensive players in American football who line up behind the defensive linemen. Their primary responsibilities include stopping the run, covering receivers, and rushing the quarterback. They need to be versatile, as they must read the offense and react quickly to different plays. There are typically three types of linebackers: middle linebackers, who lead the defense and call plays; outside linebackers, who often focus on pass coverage and edge rushing; and inside linebackers, who primarily defend against the run. Linebackers play a crucial role in a team's overall defensive strategy.