While the role of the defensive linemen is fairly consistent, the linebackers allow for the flexibility and versatility of the 3–4 scheme, and give defensive coaches nearly limitless options to confuse the other team's players and coaches. Depending on the situation, any number of linebackers can blitz, fake a blitz, "spy" the quarterback or running back, or cover receivers.
The defensive front has a standard role, but the linebackers provide flexibility within the 3–4 scheme, enabling coaches to devise numerous tactics to deceive the opposing team's players and coaches. Depending on the situation, any number of linebackers can rush, fake a rush, "pursue" the quarterback or running back, or cover receivers.