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Inside the Playbook: Over-Under Michigan's 4-3 Defense

In this post we look at the change in responsibilities Michigan's defense will face from transitioning from a 4-3 Under to a 4-3 Over.

Mark J. Rebilas-USA TODAY Sports

Much of the talk about Michigan football last year was on the offensive struggles, but the change from Borges to Nussmeier isn't the only change happening in the Michigan program this offseason. The defense, dissatisfied with their inconsistent performance last year, is also switching base fronts from a 4-3 Under to a 4-3 Over. In this post we'll look at what this change amounts to, both in terms of scheme and player deployment.

What this isn't
Let's start with what this isn't: it's not a panic move. This isn't switching an offense from a 21 personnel I-form to a shotgun spread. This is a tweak. Many of the fundamentals from last year's defense carry over and Michigan ran some Over front last year. While there will certainly be differences - which is the point of this article - this isn't a complete overhaul that negates many of the positives that the players have learned through the experience they are finally starting to show on the defensive side of the ball.

So... What is this?
I think the coaches for the most part are being very honest: this is a change to adapt to the growing use of the spread offense. This isn't just a change to get Jake Ryan in the middle. But it is a change to get a defense that is naturally more adaptable to more fronts. One of the strengths of the Michigan State defense that many believe is the reason for this change (the Spartan defense, which was easily the best defense in the league last year and a great defense at that, has very little to do with this change, for what it's worth) is that at its core it can be a 4-3 Over against a Power O team as it can against a spread team.

This also simplifies things in multiple other ways, from coaching responsibilities, to deployment of players. In the end, this touches on the foundation for the change: simplify the defense as a whole. On both sides of the ball there appears to be a common theme, that things have gotten too complex, the coaches have been stretched thin, and it's time to get back to basics, do those basics great, and grow from there. When Hoke first arrived, he made references to the 1998 defensive line, the year after Michigan won the National Championship. They struggled because they didn't have a foundation in the basics. Well, this is applying that logic to a different set of circumstances unfortunately, but with the hope that the lessons don't belie the results.

Change in Scheme
Let's explain what the change actually is. Think of a basic 21 personnel grouping. Imagine that the TE always signifies the up direction, and the ball is the center plane or ground level. The under front shifts the defensive strength under the ground level, away from the TE direction. Therefore, the 3-Tech DT is to the weakside of the formation. Conversely, the Over front shifts the strength of defensive front Over the ground level in the upward direction. Now the 3-Tech DT is to the TE side.

Here is a look at a 4-3 Under.


Here is a look at a 4-3 Over.


Change in Coverage
Because of the alignment, this does likely change Michigan's base coverage. I do not believe that Michigan will be as stringent with the Cover 4 as MSU is, but an Over front is kinder to a 2-high defense than an Under front is, mostly because of the LB alignment and how the safeties interact with the LB level. On the other hand, an Under front is more likely to have a one-high base coverage. Neither prevents press coverage or aggressive defensive play. Michigan State runs a 4-3 Over Cover 4 base, while the Seattle Seahawks run a 4-3 Under Cover 3 base. But a shift to an Over front does signify a shift to more 2-high looks.

Change in Technique - Defensive Line
One of the main simplifications of going to a 4-3 Over is the technique for the defensive line. Now, the 1-tech is much more similar to the 3-tech, to the point that they are essentially interchangeable. Similarly, the DE positions are now also similar to the point of being essentially interchangeable. Certainly, you'll still have players that are more optimal for NT and others for 3-tech, and there will still be players more optimal for SDE and others better suited for WDE, and the coaches will make that determination. But now it is both of the DTs that need to work on how to handle double teams in the middle, while both DEs work on holding the edge and take on edge blockers one-on-one.

This is different from the Under technique, where one of the DTs was taking on a double team and the other was taking on a single team and acting primarily as a penetrator only. However, when that 3-technique had to shift to an even front (as Michigan and many teams often do in their nickel package), he had to be able to take on double teams. This is the wider breadth of techniques that a primarily Under front must understand, and why an Over front adjusts in a more simplified manner.

Now, the 3-tech is still primarily going to be the better penetrator of the two, while the NT is better at holding up both blockers at the point of attack, but both DTs need to be able to do both.

Both DEs need to hold the edge and take care of the spill. The SDE will likely take on a TE rather than an OT though. He's also coming from a farther starting point, and therefore is better off being a bit faster and smaller. Some teams will prefer to play a field/boundary type alignment, but with the knowledge that more times than not, the TE will align to the field. Now, though, both DEs need to work on anchoring with their inside arm and keeping their outside arm free. They need to be better at escaping outside and pinching the EMOL to force the play to bounce.

Change in Technique - Linebacker
Due to the DL alignment, the linebackers can be a little less protected than they are in an Under scheme. However, they aren't necessarily completely unprotected, and tweaks in the DL can allow for greater LB protection.

Again, here's a normal 4-3 Over.


Here's a 4-3 Over G.


By shading the NT out, the WILL sees greater protection than he otherwise would, as the OG has to work harder to get to the second level.

Likewise, the 3-tech can shade out to help protect the SAM from the OT. Here is a 4-3 Over I.


There are several ways of utilizing personnel within the 4-3 Over, but it is clear that Michigan will be using the OLBs more as slashers while the MIKE is set to take on the initial blocker. This protects the OLBs, and changes much of Michigan's scheme from working outside and squeezing the play back inside, to penetrating on the inside and forcing to bounce outside to the leverage players. This is expected for more 2-high type schemes.

I expect Michigan's 3-tech to work over closer to the OT a bit more and protect the SAM;  with Ryan taking over at MIKE and Morgan at WILL, those players both have more experience in taking on blockers. Meanwhile, Ross is playing SAM and will be the ultimate slashing type LB, and also pick up the TE in coverage, where he needs to improve on last season's performance.

Basic Responsibilities

Side Align Tech Key Run To Run Away Pass
Strong 9 tech TE D Gap to Alley C Gap - Chase Outside Contain
Strong 3 tech OG B Gap B Gap - Squeeze A Gap B Gap
Weak 1 tech C A Gap A Gap A Gap
Weak 5 tech OT C Gap to Alley C Gap - Chase C Gap Contain
Strong 60 tech OG to RBs C Gap A Gap - Slow Pursuit Coverage
Strong Strong 00 OG/C to RBs A Gap B Gap Coverage
Weak 40 tech OG to RBs C Gap (Alley) Slow Pursuit Coverage

There is much more we can get into, particularly when rolling in coverage into the Over scheme. I do not believe that Michigan will strictly be an Over team, however, I think it will be their base scheme. I also don't think they will be as tied to a single coverage scheme like MSU is to the cover 4. I still think Mattison wants to be multiple, I think he wants to mix in a larger variety of blitz types (whereas most of MSU's blitz package has cover 3 behind it). But ultimately, this is a move to simply the defense in multiple ways in an attempt to have them play more instinctively, quicker, and aggressive.