Last week we took our first foray into the world of coverage shells with looks at Cover 0 and Cover 1 schemes. We saw how those two schemes rely almost exclusively on athleticism in man coverage to disrupt and contain an offense.

We’ve also seen how playing without deep coverage can be a liability to a defense if the offense manages to force a mismatch, the defense can’t generate pressure, or the defense lacking the athleticism to match up.

Let’s see how shifting players from man coverage to zone coverage can change how a defense looks.

Cover 2

Following the theme of the Cover 0 and Cover 1 shells, Cover 2 is named for the two players covering the deep apart of the field. Usually, these are the two safeties playing zone coverage behind the rest of the defense.

The Cover 2 coverage scheme has been around a long time, evolving in response to the growth of the passing attack in NFL offenses in the 1960s and '70s. Arguably the greatest defensive dynasty of all time, the "Steel Curtain" defense fielded by the Pittsburgh Steelers of the 1970s was based on Cover 2 principles. In 1976 that defense came up with five (5) shut-outs, and gave up just 3.1 points per game. It’s a feat that is unlikely to be repeated ever again — especially considering how the NFL’s rules have come to favor offenses — but it does show the potential of the Cover 2 shell in the right situations with the right personnel.

For the New York Giants a Cover 2 shell would look something like this:

As you can see, the safeties provide split the field in half, providing help should either wide receiver run a deep route. The coverage underneath, from the cornerbacks and linebackers, is determined on a play by play basis.

For the Giants, the deep safeties would likely be Landon Collins and Darian Thompson in base packages. However, it would likely be more common to see this coverage shell in nickel sets, with a better coverage safety such as Nat Berhe, Mykkele Thompson, or Bennett Jackson, manning the other half of the field with Darian Thompson. In that case, Collins would likely come down and replace a linebacker that rotated off the field.

Under Perry Fewell, the Giants would frequently run off-man or soft zone coverages underneath. While that allows defenders to effectively cover the entire field, defend the run (and screen passes) and keep eyes in the backfield to come up with turnovers, it also made the defense vulnerable to quick passes.

But just because zone coverage underneath a Cover 2 shell is common, it doesn’t mean that all Cover 2 defenses are zone defenses. It is perfectly acceptable for cornerbacks to play man coverage under a Cover 2 shell.

The Cover 2 is a balanced coverage scheme, and can effectively blanket the entire field with defenders, but it isn’t without its faults. A defense that relies on zone coverage also demands communication and discipline from the defenders. Zone coverage demands that the defenders remain in their area of responsibility, covering the offensive players that enter them, and "passing them off" to other defenders as they exit the zone. If a defender doesn’t recognize that a player is entering his zone, or stays with the receiver as he enters another defender’s part of the field, the breakdown in coverage often results in a big play for the offense.

Another issue with the Cover 2 is that with as many as seven defenders devoted to coverage, a defense using a Cover 2 shell relies on the front four, the defensive line for a 4-3 defense, to generate pressure on the quarterback. With the safeties in a deep zone coverage and the linebackers working to cover any underneath routes run by tight ends, slot receivers, or running backs, a defense might not have the players available to blitz. Finally, with both safeties deep, the Cover 2 shell takes the strong safety out of run support. With defensive tackles like Damon Harrison and Johnathan Hankins, the Giants might be willing to surrender some run-stopping ability to take the deep pass away from offenses in the right situation.

Cover 2 shells can also be prone to opening the middle of the field as the safeties move toward the sidelines to help the cornerbacks in coverage. Let’s take look at one way defenses have addressed that weakness.

Cover 3

If a defense is looking to keep most of the strengths of a Cover 2 shell while addressing some of its more glaring weaknesses, they might turn to something like the Cover 3 defense. As the name suggests, the Cover 3 has three defenders in deep zone coverage. But while Cover 2 usually sees the safeties playing deep while the corners and linebackers play a variety of coverages underneath the safeties’ zone coverage, Cover 3 takes a different tact.

Cover 3 resembles Cover 1 with the free safety playing the deep middle while the strong safety stays close to the line, maintaining an eight-man "box.". However in Cover 3 the cornerbacks make hard drops into deep zone coverage off the snap, dividing the field into thirds.

By maintaining an eight-man box and with the free safety able to roam the middle of the field, the Cover 3 effectively addresses two of the more glaring weakness of the Cover 2 shell, the run defense and the middle of the field. The Seattle Seahawks regularly use the Cover 3 shell behind their hybrid defensive front. With Earl Thomas’ range and instincts at free safety, and Kam Chancellor’s ability to blur the lines between weak side linebacker and safety, they are able to effectively limit offenses’ options.

But like every defensive scheme, the Cover 3 has its weaknesses.

First and foremost, the hard drops that the corners have to make to get into deep zone coverage generally requires that the defense is telegraphed to the opposing quarterback before the snap.

In this defense, the outside linebackers, or sometimes an outside linebacker and the strong safety, drop into shallow zone coverage to cover the area vacated by the corners at the snap of the ball. Unless they are uncommonly athletic, the average linebacker is no match for a receiver in coverage, and the Cover 3 can be vulnerable to quick, well-timed passes into those short zones. While this can be frustrating for a big play offense or an opponent playing from behind, and creates opportunities for turnovers, the "bend but don’t break" philosophy does allow the offense to move the ball.

However, by the same token with three defenders deep and eight close to the line of scrimmage, if an offensive line is stout enough, the offense could also choose to flood the deep zone with vertical routes. Because of zone coverage’s reliance on discipline, sending three or four vertical routes against a Cover 3 shell will either prevent the free safety from helping one of the corners with a double team, or force the defense into a numbers game that will leave one of the receivers open. It’s a risk, because the quarterback has to stay on his feet long enough for the routes to develop.

Tampa 2

Question: When is a Cover 2 really a Cover 3 shell?

Answer: When it’s the "Tampa 2" defense.

The Tampa 2 defense gets its name from the defense the Tampa Bay Buccaneers ran under Tony Dungy. It was a Cover 2 base defense, but at the snap would suddenly become a Cover 3 after the snap, typically with the cornerbacks playing zone coverage underneath.

The Tampa 2 starts out exactly like the Cover 2 shell with two safeties in zone coverage to take away deep passes. Generally the corners play zone coverage, but that isn’t a necessity. The wrinkle that separates the Tampa 2 from the Cover 2 comes when a linebacker — generally a middle linebacker, but the more athletic outside linebacker could do it as well — drops into a deep zone coverage at the snap, effectively turning a Cover 2 into a Cover 3 shell.

The Tampa 2 relies on two personnel traits that can be very hard to find. First, it relies on general team speed to cover as much of the field as possible, and an athletic front four in particular. Because the Tampa 2 devotes five players to coverage, the remaining six players must be able to disrupt the offensive play. Having an athletic defensive front that can pressure the passer and disrupt running plays is crucial to this.

Second, the Tampa 2 needs an exceptionally athletic middle linebacker. The prototype here is former Chicago Bear Brian Urlacher. Urlacher was a rare athletic talent who, despite having a linebacker’s build, played safety in college. He was able to retain that range and athleticism despite adding weight to play linebacker in the NFL. Urlacher’s physical abilities let Lovie Smith’s Bears successfully run the Tampa 2 defense Smith learned from Tony Dungy. However, players with that combination of size and range are few and far between, making it difficult to run a true Tampa 2 in the NFL.

Talking Points

• Do more players in zone coverage necessarily mean a softer or more passive defense?
• Are the Cover 2, Cover 3, and Tampa 2 coverage shells viable as a part of a base defense in today’s NFL?
• Do the Giants have the personnel to run any of these coverages on a regular basis — should they?
• Put yourself in Spags’ shoes: If for some reason you HAD to choose, which of these three coverages would you run?