Spying the quarterback

The spying on the quarterback is the sole responsibility of the detached defender. Traditionally, the linebacker or defensive back must follow and repeat the quarterback’s move. It floats off the line of scrimmage. This player is the opposition of the pocket passer.

Spying can be risky because the offensive linemen can detect the spy and neutralize it. Conversely, the quarterback can notice and make the pass or hide from the coverage. Thus, the QB contain strategy is more desirable if the defense goal is to prevent the QB from marching outside.