Stout Assessments: coverage shells

Over the past couple of weeks, I’ve touched upon the 2017 Kansas City Chiefs tendencies with their outside linebackers in coverage and their tendencies involving their pass rush and blitzing.

The next tendencies to examine involve those tendencies of the secondary and their coverage shells. However, before we tackle those tendencies, I wanted to write a quick refresher on some of the basic coverage shells the Chiefs use, so we’re all on the same page going into the tendencies of the secondary, as well as the 2018 season. This may be an old hat for a lot of you, but for some, this may shed some light on terms that get thrown around without much explanation.

So without any further ado, let’s dive into our coverage shell refresher!

Cover 0

Cover 0 is a coverage shell meaning exactly what it says: zero deep defenders.

This coverage is typically run near the opposition’s goal line, which makes the above example even rarer. The ideal outcome in a Cover 0 shell is to bring a lot of pressure with the front, as there are exactly as many defenders with coverage responsibility as there are eligible receivers. This shell is a major gamble at this spot on the field, as any misstep in coverage could lead to a huge gain by the offense.

It’s usually accompanied by press coverage to disrupt timing and force the quarterback to hold onto the ball a split second later with extra rushers coming. It’s executed well in this example, as the quarterback is forced to release the ball early and off his back foot, resulting in an errant throw.

Cover 1

One of the most common coverage shells Bob Sutton implements is a Cover 1 shell.

This means there is one deep safety whose coverage responsibility is the entire deep section of the field, from sideline to sideline. The rest of the members of the secondary are in man-to-man coverage (yes, even Peters on the lower side of the play). This shell is very flexible because there is typically an extra safety or linebacker to offer run support, bracket a receiver, spy on the quarterback or play a shallow zone.

However, the deep safety in Cover 1 is required to be a very rangy defender to run this shell effectively, which makes it difficult for some teams to run. In this example, the Chiefs are able to send a blitz while the Philadelphia Eagles run a rub route at the top of the screen.

This means the safety has to stay home to help the boundary corner trailing the slant receiver, but good coverage by the slot cornerback results in an incompletion.

Cover 2

The Cover 2 coverage shell is one in which the two safeties split the deep part of the field in half, each responsible for half of the deep coverage.

Cover 2 is less flexible than Cover 1, as there isn’t the extra safety to put into the box. However, unlike Cover 1, your Cover 2 safeties are not required to be as rangy (as they’re only covering half the field), meaning it’s a slightly easier scheme to run with less athletic safeties. The underneath defenders can be in a zone coverage, and a middle linebacker can even drop into a deeper middle zone, turning the shell into what’s famously known as a “Tampa 2” look.

The example shown above is a “Cover 2 Man Under” look, also known as a Cover 5 shell. In this look, every underneath defender is in man-to-man coverage while the defense rushes four. Typically in Cover 2 Man Under looks, the defenders will play trail technique, in which the defender will sit on the inside hip of the receiver and take away a throwing angle, knowing that there is a safety playing top down and can collapse on any pass attempt over the top of the defender. This example shows great coverage, and Derek Carr has nowhere to go with the ball, forcing him to take a costly sack.

Cover 3

Bob Sutton’s go-to zone coverage shell is the Cover 3.

In a Cover 3 shell, the defense will have one deep safety, similar to the Cover 1 shell, but on the snap, the outside cornerbacks will drop into a deep zone coverage, splitting the deep part of the field with the safety into thirds, while the other safety, a linebacker, the nickel/dime linebacker, and the nickel cornerback will become the underneath zone or man defenders.

In this scheme, you gain a lot of the advantages of the extra safety flexibility of a Cover 1 scheme (primarily run support) while not requiring the deep safety to cover the entirety of the deep part of the field. This scheme can be susceptible to passes to the flat, due to the cornerbacks evacuating the area and another defender having to rotate out to cover the flats. The example I’ve shown above is a very generic Cover 3 example, demonstrating the cornerbacks getting depth alongside the deep safety.

Cover 4

The Cover 4 coverage shell (if you haven’t picked up on it yet) splits the deep part of the field in fourths, with two deep safeties and two CB’s. This is more commonly known as a “prevent” defense, as it guards against the deep pass but leaves itself open to short and intermediate passes. The Chiefs didn’t like to run Cover 4 shells, instead relying on their Cover 3 zone in 2017.

Cover 6

The Cover 6 coverage shell is a hybrid shell on the back end of the secondary in which half the field is defended by one player and the other half is defended by two players, making a “quarter-quarter-half” shell.

Typically, the half of the field covered by a single defender tends to be the “deep safety” role of a Cover 1 or 3 shell, while the strong safety and the opposite cornerback split the other half of the field. This does help keep the strong safety from having to cover as much ground, allowing him to come forward in run support more readily. However, it still suffers from the disadvantages of the Cover 3 scheme, giving up the flat as the cornerback evacuates the area into zone. The Chiefs typically like to have the second safety free to roam, as they do in the Cover 1 and 3, so Cover 6 looks aren’t as common.

That’s just a rough outline of each coverage shell that the Chiefs typically run as a refresher prior to going over some of the Chiefs’ tendencies in 2017.

There are many variants and hybrids to each one of these schemes, crafted to stop specific offensive schemes. In my next post, I’ll cover a “go-to” look that Bob Sutton used much of the time last year, which should show some of the more dynamic elements of his coverage schemes and can help illustrate just how difficult it is to identify some of these coverage shells on the fly for offenses.

Be on the lookout for that, and then we’ll round out 2017’s pass defense with the coverage tendencies!