Within the linebacking corps, they are often divided into middle linebackers, sometimes called inside linebackers, and outside linebackers. The middle linebacker, often called the "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 unique position to blitz, a type of defensive maneuver where the player rushes unexpectedly into the offensive backfield in an attempt to disrupt a running play or sack the quarterback on passing plays. Besides "Mike", other male names such as "Sam", "Will", or "Jack", among others, are commonly used to refer to various linebacking roles, to ease communication in play-calling.