Usually in this space I like to talk about a thing that Michigan did differently to confound their opponent or add to the toolkit. This week, after a game when Harbaugh and his staff thoroughly outclassed Dantonio and his in all three phases, I'd like to discuss a thing Michigan has had in their kit for as long as Don Brown has been here, and how Michigan State came in with a gameplan to defeat it (and yes, how Michigan adjusted and went back to dominating).

That's because so many people were talking before, during, and after this game about Michigan's passing down coverage, what Gus Johnson, Joe Klatt and Urban Meyer were calling "Brackets Coverage" and which Brown, James Light, and this space shall call "Doubles."

Doubles Coverage

Unfortunately the guy who did the best job of explaining how Michigan prefers to defend passing downs was Urban Meyer, right before this game, so let's see what he had to say (I recommend the full video on Fox):

He's simplifying it, Urban's spread offensive mind thinking of it in terms of numbers: more defenders than offensive players over here, and over here, win: defense. But the basic gist of doubles coverage is understandable to every kid who's ever played playground football: play man and use the safeties to double-team two of the most likely receivers:

Even on this level, who gets doubled is the important part; the how they get doubled is getting into the weeds.

[Which we shall, after THE JUMP]

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Who's getting doubled matters because you're trying to cover the first read, and maybe the second read too. Say you've guessed the quarterback's first read. You've taken away the easy thing his play was supposed to create, AND the time he spends figuring this out translates to time your pass rush can use to get home. So he moves to his second read, and that's doubled. All of your rushers get to roll again. By this point he's on to his third read, and by design that's not supposed to be a very good one. Also (and this gets into the how), by this point the routes are declared and the double-teams have become dominating single-teams with zone defenders backing out and reading the quarterback's eyes. And since it's not always obvious that a bracket's in place, a less experienced quarterback is liable to throw a pick right to the safety while trying to lead his receiver away from the coverage.

Figuring out the order of the offense's reads so you can double those of the highest priority is somewhat guesswork, somewhat based on tendency, and a lot of strategy. Often you're trying to directly mess with the quarterback's reads so he'll fall into the trap of reading your doubled receivers first. You're also using your scouting of the offense.

With Michigan State for example we know:

• Their running backs aren't very good receivers
• Their offensive line is three freshmen and two (Campbell and Reid) of the most atrocious longtime starters in modern Big Ten history, so they're likely to need TE help.
• The tight end is a walk-on transfer whose 19 career catches were almost all uncontested on 1st and 2nd downs.
• Cody White far and away their biggest receiving threat.
• Their 3rd down specialist is on the field at slot receiver.
• You see how they align and there are three eligible receivers on the short side flanking the slot, their #2 receiver has virtually half the field to himself, and their #1 receiver is on the outer side of the numbers.

So Michigan's safeties can infer that White, the #2 receiver, or the slot are the most likely first reads, and by White's alignment in the bunch, and from scouting MSU all year, you can guess his route is a sideline fade. So they make the doubles call: bracket the H and the X, leaving your best corner on the field (Ambry) one on one with State's best receiver against a low-percentage route, and your linebackers alone on the tight end and running back since they're likely to stay in and block anyways.

How they cover these guys is pretty interesting. It's not a pure double-team so much as a read coverage—they're optioning the receivers so wherever he goes he's running into a defender. Note that coverages often denote receivers by counting eligible guys from the sideline, so the most outside receiver on either side is #1, the next guy in is #2, and so on.

There are four calls as far as I can tell in Brown's playbook (I have the 2013 Boston College one), and two techniques.

• CONE (cornerback + safety on #1) or DEUCE (cornerback + safety on #2). This means the safety takes the receiver if he goes up or inside, with the cornerback staying on him to cover anything over and outside. If the receiver goes HARD inside (it's got to be blatant) the safety takes over and the corner can drop into a Cover 2 zone, attacking where he sees fit.
• VICE (safety + viper/nickel/LB) or RABBIT (safety + cornerback). This flips the inside-/outside equation. The low man (let's say nickel here) has the receiver on anything inside up to 12 yards while the safety is over the fade. If the receiver goes outside the safety can charge on that (and try to pick it off) while the nickel looks up wherever the #1 went and charges on that, reading the QB's eyes and ready to break.

Cone/Deuce is a traditional bracket that will deter most throws. Vice/Rabbit is a more aggressive style that allows the man to man guy to play slants and the like super-aggressively because he has help over the top—it's meant to generate a throw that results in a breakup or interception because it looks like the receiver has leverage right up until he doesn't.

(The last label on the graphic above is "Green Dog." That's a general assignment for a linebacker who's covering a running back or tight end—if the guy they're covering stays in to pass protect the LB has the green light to blitz.)

I talked about this "Switching" system after Penn State. At the time we were just watching how Lavert Hill (CB on the bottom) and Brad Hawkins (safety on the bottom) react to the crossing route. The actual coverage is Doubles and those two are running a Cone. The X receiver's hard inside break relieves Lavert Hill of his Cone duties since Hawkins is going to come down all over it. Watch as Hill makes his read then backs into a zone where he can be of assistance in case the H receiver being covered by McGrone is also crossing.

Also note that Metellus is staying on top of the running back who, in Penn State's offense, is a pretty decent receiver, allowing Dax Hill to play that guy inside aggressively. That's a Vice. Finally, watch Ambry Thomas. He starts up, preventing a free release for the receiver, and then when the guy releases Ambry is taking him to the sideline, just as he did versus Cody White in the MSU example. On the opposite side you see Khaleke doing the same with the tight end.

Anyone whose man goes down the sideline has only the sideline for help—the brackets are there to provide coverage to either side of any in-breaking route. But the brackets can't cover everybody. Both Khaleke and Ambry are playing inside of those sideline routes, not expecting safety assistance. On the other hand Metellus and Hill both let their crossing route receivers go and convert to zone defenders, because they know they have brackets (Dax Hill and Brad Hawkins, respectively) inside to take over.

Doubles Disguises

You can think of this coverage as kind of like drawing up a blitz. You overload one side, move some guys into gaps they're not expected in, and hope the protection breaks down before your coverage does. When you blitz like that, the better you disguise who's coming and from where, the better chance you have of getting through, right? And with blitzing the converse is also true: if you telegraph where you're blitzing, they'll pick it up and throw it to wherever the blitzer just abandoned.

The same is true for Doubles coverage: if the quarterback knows ahead of time which receivers are doubled and by whom, he'll skip them and move directly to a single-covered read, which should be getting some kind of leverage. So like a blitz, you try to show a lot of different looks before doubles to make it hard for the QB to see which guy's getting the bracket. For example, a cornerback in CONE coverage will often set up inside the receiver to make it look like he's in Don Brown's Cover 2 trap coverage.

Disguising the coverage. He gets to outside leverage after the snap. Show trap coverage, play Cone.

— James Light (@JamesALight) March 31, 2017

Urban showed an example like this one from Notre Dame, where Michigan shows a three-high look to disguise the coverage.

Look at the setup before the H goes in motion and see if you can guess who's getting the doubles treatment, and from whom. I'm guessing you were wrong:

Screwing with Doubles

Phew. So I got through all of that because I had to explain that this coverage is what Michigan State was planning to mess with. And the play we're on right now is a good example. For one, the assignments will have to switch when the H goes in jet motion, with Hawkins turning into the man-to-man safety on #3 and Dax taking Brad's place as the Cone safety on #1.

State here is running a play I know as "Seattle" that's normally a zone-beater, but MSU is using it to exploit Michigan's plan to use all of their backside DBs to double the backside receiver, hoping to clear out the double with that guy, and leave just a wheel-route-chasin'- MLB and a late-arriving safety to deal with RB wheel route and a jetting slot receiver following.

Watch McGrone's coverage here. He has to dodge the pick from Cody White's route, then momentarily doubles the first read with Hawkins, who's in man on the slot who came across. But for Uche teleporting past a Spartan-quality guard that RB is about to slip by McGrone and add to Twitter's stockpile of undefeated wheel routes. That's Lewerke's first read, and he's in single coverage on a linebacker with his arm up:

MSU's big fall camp thing this year was coming up with these games to defeat Doubles coverages. They came in bunching their receivers together, using one receiver who's probably not doubled to split the double-team and pick the coverage. As you no doubt recall, that led to some early 3rd and long conversions:

Remember in a "VICE" call the idea is the outside player is supposed to drive hard inside, playing slants with abandon because the safety is getting over anything that turns out. That's why Metellus is apparently out in no-man's land instead of hammering down on the slant here. The guy who was supposed to get under the slant was Ambry Thomas, but he's trapped by the WR's move outside and then a natural pick from the tight end's route. Replay:

They also took advantage of the expectation that the defense couldn't help but double MSU's best receiver if they sent him vertical, then sent two more eligible receivers right at the cornerback left outside, hooking one of them for a quick snag.

It worked a second time, even though Ambry was prepared for it:

And it could have worked again later in the game when Dantonio added the running back as fourth wide receiver outside the bunch, and despite a 3-man pass rush (with Dwumfour dropping) there was a guy open, albeit not the first or second or probably even third read, and by then Luigi Vilain has healed two broken legs and beaten whatever passes for a Sparty left tackle these days:

All that coverage committed inside is useless if the doubles get sucked deep by a big burly guy and the offense is just lining up outside. Until Michigan adapted by shifting their alignment.

Lock & Levels

For Michigan's response we have to back to Woodson and again I recommend the whole thing:

Lock and levels is a strategy for playing man to man against these bunch sets. The idea here is if you've got a big burly receiver or tight end flexed out in a bunch to clear space, just don't let him get a release until your buddies are on the tail of their dudes.

This should leave said buddies free to stay in man coverage on their chosen matchups when the offense tries to flip that.

Sure you're giving up the surprise a bit, but look what you gain. Cody White is delayed off the line by Hawkins "locking" him at the line of scrimmage for a second, and that leaves plenty of room for Khaleke to follow the tight end outside and Vincent Gray to collect his guy. They're the levels: by setting up at different depths they have lanes to get around each other, and don't need to swap guys to cover.

But you can absolutely play Doubles—which is inherently a man defense—with this technique as well. In fact I think this is an example. It looks like Cover 1, i.e. Michigan's base defense, which is why they have the luxury of sending five guys at the quarterback. And technically it is, since there's a single high safety and everybody else is playing man to man. But look at the picture above, where Metellus's eyes are. He's watching Cody White, the guy Hawkins is locking, not the quarterback's eyes. And note the technique that Ambry Thomas is playing against Julian Barnett at the bottom of the screen.

That's not how a cornerback plays in Cover 1. That's how a cornerback plays on an island, using the sideline as his help and trying to force the receiver as close to that as possible. Because he doesn't have help over the top. Because Metellus is playing his doubles technique on the other side. And now with the one thing they prepared for this game taken off the table, MSU was out of ideas except loft it up to the guy in single coverage. MSU would average 3.4 yards per play for the next five drives, with an interception, a fumble, and three punts, and never enter Michigan territory again. Maybe next year.