Why Not More Reverse Cover 2?

During Super Bowl XLIII, John Madden correctly noted that the Steelers were running a “reverse” Cover 2 defense. The Cover 2 defense has the cornerback funnel the wide receiver to the safety, lined up off the line of scrimmage. The cornerback tries to (legally) slow up the WR when the ball is snapped, and tries to make sure he doesn’t get outside or inside, whichever way the defense wants him to go.

In the Super Bowl, the Steelers switched the safety and the corner. Strong Safety Troy Polamalu lined up over the wide receiver and bumped him, then released him to the cornerback to cover him deep.

Safeties tend to be bigger and slower than cornerbacks. Many defenses are designed to feature run-stopping safeties, the proverbial “8th man” in the box. As a result, safeties are not as good in coverage, yet are expected to be the last line of defense against the other team’s speediest players.

Thus, it makes sense to put them near the line of scrimmage to provide a physical presence against both wide receivers and also in run support. By keeping corners 10 yards off the line of scrimmage, you enable them to take advantage of their smaller, quicker frames. The Indianapolis Colts, the leading Cover 2 team in the NFL, does this sometimes.

The scheme makes so much sense I wonder why they don’t do it more. I’m guessing because when running other coverage schemes the safeties and corners would have to know too many different positions and coverage responsibilities.