A couple years ago, I did an outline of Mike Zimmer’s defense, but didn’t really get into a lot of detail on the nuts and bolts of it. But as it’s been a top 5 defense ever since, I thought I’d take a look at what has made the Minnesota Vikings version of it so successful.
Let’s Start with the Basics
DEFENSIVE FRONT 7 FORMATIONS
Mike Zimmer employs a 4-3 base defense, meaning he has 4 defensive linemen and 3 linebackers when an offense has 2 wide receivers (WR). The more wide receivers, the more cornerbacks (CB) (and few linebackers (LB)) he uses.
So typically against 3 WR, he’ll have 3 CBs and 2 LBs (aka nickel), and against 4 WRs he’ll have 4 CBs and 1 LB (aka dime). There are special situations where something different may be used, but these are the most typical match-up formations.
The nickel formation is used most (over 50%), followed by base (@ 40%), then dime.
SHELL COVERAGE FORMATIONS
There are six basic shell coverage formations used in the NFL: Cover-0, Cover-1, Cover-2, Cover-3, Cover-4, and Cover-6. Here is a primer on them. And here is another piece on team tendencies for each coverage type.
The Vikings under Mike Zimmer use primarily Cover-1 and Cover-2 shell formations in their secondary. This means they have either 1 or 2 deep safeties (Cover-1 or Cover-2). In a Cover-1 shell, the cornerbacks are typically in man-to-man coverage. In Cover-2, they can play either man or zone coverage.
Here is what Cover-1 and Cover-2 shells look like in the Vikings’ 4-3 base defense:
Alternatively, in the Cover-2 shell shown above, the CBs can play man-to-man coverage on their receivers, rather than drop back into zone coverage, and the linebackers cover the tight-end and running backs, as in the Cover-1 graphic.
These are the basic looks the Vikings will show initially on almost every play, the only exception being when they are in nickel (or dime) coverage, and there is a 3rd (nickel) or 4th (dime) CB replacing a linebacker on a slot receiver.
The Vikings, like every NFL team, use both man- and zone coverages at times. Typically the Vikings CBs play pure man-to-man coverage about a third of the time. The rest of the time they play either zone coverage, or some sort of hybrid man/zone coverage. There are also a couple different types of man-to-man coverage the Vikings use.
Press-man coverage is when the CBs line up on the line of scrimmage against their receiver and attempt to jam them to prevent them from getting into their route and disrupt the route timing.
Off-man coverage is when the CB drops off the line of scrimmage and give their receiver some cushion, but still cover them one-on-one. This makes it less likely for the receiver to beat them on a deep route.
The bottom line in terms of basic front 7 formations and shell coverages is that the Vikings use very few of them. Most of the time when the defense breaks huddle they will show a 4-3 front with a Cover-2 shell, in either base or nickel personnel groups.
That simplicity at a basic level is a key aspect of Zimmer’s defense, as it masks what his defense will actually do, making it difficult for quarterbacks and offensive coordinators to audible and scheme against it.
Okay, so much for the basics. Let’s move on to pre-snap looks and movements.
Pre-Snap Looks, Movement and Changes
Once the Vikings defense breaks huddle, they may initially show a 4-3, cover-2 look, but it doesn’t always remain that way by the time the ball is snapped. Often times the defense will shift and move in various ways pre-snap, which can create confusion and add to the degree of difficulty for an offense to execute their play successfully.
Here is are a couple examples vs. the Rams:
Notice in the first clip, a 3rd & 8 situation, a few key movements prior to the snap:
- an interior defensive linemen moves to the B gap between the guard and tackle.
- the linebackers move up into the interior A gaps between the center and guards.
- the single high safety, Anthony Harris, moves down toward the line of scrimmage
- Harrison Smith, the other safety playing up near the line of scrimmage, moves all the way back to the single high safety spot.
You can see Rams QB Jared Goff audibling as these movements take place, perhaps trying to change the play or protection, and creating some confusion for the young QB and the Rams offense.
On the resulting play 3rd down play, the Vikings were able to pressure Goff as Tom Johnson (who moved outside the guard) took advantage of a slight hesitation by the guard- waiting to see if Barr blitzed or not- to get by him on the outside, forcing Goff to step up into traffic, then outside to a throwing lane where Kendricks pursued him into a bad throw.
In the second clip, a 2nd & 10 situation, again there is movement in the Vikings defense, this time more in response to changes in the Rams formation, and audible by QB Goff. The Rams had shown a 4-WR look initially, with tight-end Tyler Higbee lined up outside the numbers against Trae Waynes, and running back Gurley in the backfield.
The Vikings show initially what looks to be off-man coverage with a single-high safety in a nickel package, the defensive ends out wide (9-technique), and the interior linemen both playing off the guards (3-technique).
Apparently that wasn’t the look the Rams were hoping for, so Goff audibled a change, bringing in the TE Higbee.
The Vikings also changed, with the interior lineman moving inside, Griffen moving off-tackle (7-technique), Waynes showing press-man coverage on the wide receiver now, Barr covering the TE Higbee, and Harrison Smith moving back to present a Cover-2 look.
The resulting play was a middle zone run, which may have been called seeing the interior linemen lined up outside the guards initially, making it easier for the Rams offensive line to block, but was defeated when Linval Joseph and Tom Johnson moved inside after the call was made, clogging the middle and stopping it for a loss.
In each situation, both forcing, and reacting to, change, the dynamic nature of Mike Zimmer’s defense pre-snap makes it more difficult for the Rams offense to execute effectively. The last second changes make it difficult for QBs and offensive linemen to react, and often take away any pre-snap read a QB may have.
A more static formation and coverage can be more easily read by a good quarterback pre-snap, allowing him to get a good idea where he may go with the ball, if he needs to change the play, and/or protection scheme.
Taking away the pre-snap read from the quarterback also makes his job that much more difficult.
Imagine you are an NFL quarterback. Every play, you have 3 seconds from the snap of the ball to get rid of it before defenders get to you. That’s not a lot of time. So any clue or information you can gain- pre-snap- that helps you know where to go with the ball, gives you an advantage. Reading a defense as you step up behind center or survey from shotgun formation can often give you the information you need to get the ball out sooner.
But movement and changes by the defense pre-snap can make it difficult to get that information, taking away that advantage. It can also put pressure on you to make changes to the play or protection, adding the difficulty of communicating and executing those changes effectively at every position.
Any breakdown in that process can give the defense an advantage or mismatch that enables them to better execute their job of stopping you.
In Part II, I’ll look at disguising coverages and other elements of Mike Zimmer’s defense that create more problems for offenses to overcome.