Since the Ravens have been re-signing their own in free agency (aside from Steve Smith, whom my fellow BSL Ravens Analyst colleague Dan Bryden already discussed), I decided to go ahead with the next part of this series rather than wait for a FA to analyze. Part two of the All-22 Playbook is all about defensive coverage shells, so I’m going to break down the typical schemes you see in the defensive backfield.
Cover 0 is an aggressive coverage scheme designed to get pressure on the QB. The zero equates to the number of safeties over the top, so the pass rush really needs to be successful or else the offense has a huge advantage. Below is a great example of Cover 0 from the NE @ MIA game from 2013. Miami ran Cover 0 in the redzone over and over again versus the Patriots and had a lot of success. The idea is that Brady can dissect almost any defense but can’t handle pressure as well.
There are two common versions of Cover 1, but both keep a single high safety in the deep middle. This defense requires a very good free safety, like Jairus Byrd (or Ed Reed in his prime). The two most common variations are Cover 1 Man Free and Cover 1 Robber/Rover.
Cover 2 is named for the two safeties who split the deep portion of the field in half. There are two main variants of this defense: Cover 2 Man, which asks the rest of the defenders to play man coverage underneath of the deep safeties, and Tampa 2 – named for Tony Dungy’s Tampa teams, which developed an all-zone version of the Cover 2 defense. The whole field is split up into smaller zones and, most notably, the middle linebacker drops into a deep zone between the two safeties. This defense requires a very athletic linebacker who can drop 15-20 yards deep and cover well. Brian Urlacher was probably the most successful Tampa 2 ILB of all time.
Cover 3 is a very popular defense in the NFL right now because it’s well-balanced against both the pass and run. Many of the league’s best defenses – such as the Steelers and Seahawks – like to run this scheme. In Cover 3, the free safety and the two outside cornerbacks split the deep part of the field into thirds. The strong safety and the linebackers then split the underneath portion of the field into four zones – two flat/curl zones and two underneath middle zones.
Cover 4, also known as Quarters, splits the deep part of the field into four parts. The two safeties and the two outside corners each take a quarter of the deep zone, while the linebackers split the shorter part of the field into three zones. This defense is particularly adept at preventing the deep pass, but it also allows the safeties to play downhill against the run. Below, you see San Francisco in Cover 4 against the Falcons’ empty backfield set.
Cover 6 is a lesser-understood coverage shell, but it’s used often in the NFL these days. It’s considered a “hybrid” coverage that combines rules from both Cover 2 Man and Cover 4, and it blends the best aspects of both defenses.
In the diagram below, you see the free safety (F) in a deep half responsibility. The WILL linebacker (W) and the cornerback (C) on his side of the field are in man coverage, just like they would be in Cover 2. On the other side of the field, the strong safety ($) and the cornerback (C) are in Cover 4 zones, so they’re each covering 1/4 of the deep zone. Beneath them, the MIKE linebacker (M) and the nickel corner (N) are in zone coverage (like they would be in Cover 4). The nickel has the curl/flat zone and the MIKE linebacker has the middle zone.
NOTE: Cover 7 rules are not standard across systems, as it’s a very malleable coverage scheme. I’ve included it here because it’s an important tool for many great defenses. But please do not think this description is general. Rather, this is how Nick Saban runs his Cover 7 scheme. I’ve chosen his because it’s a fairly simple way of understanding the scheme.
Ok. So, with that out of the way… Cover 7 is a little more complex than the schemes above because it’s designed to react to the offensive formation.
At its most basic, Cover 7 looks a lot like Cover 4 – but with built-in man coverage and route-matching rules. The roles of each player in the defense will change depending on the look the offense gives and by the routes that the offense ends up running. Below is an image from Nick Saban’s Alabama defense:
On the left side, the cornerback (C) has two primary possibilities. He can play man coverage on the X receiver by himself, or he can bracket the receiver with the free safety (F). The WILL linebacker (W) also has two responsibilities: man coverage versus the running back (A) or the 1st crossing route to come underneath his zone. The MIKE linebacker (M) is responsible for the #3 receiver (F). The strong safety ($) is responsible for the tight end (Y) on a vertical stem. The SAM linebacker (S) is responsible for the flat on the right side of the defense, and the cornerback (C) on the right side is responsible for for playing man coverage against the Z receiver.
As you can see, some of the defenders are in strict man coverage while others have both zone and man responsibilities, depending on what the offense does. For the latter defenders, if a man runs out of their zone, they revert to Cover 4 zone rules.
Confused? I understand. Luckily, people much smarter than me have discussed Cover 7 in much greater detail here and here. I highly recommend reading these two excellent articles for a better understanding of this complex defense.