Michigan State's defense is specifically designed to overwhelm college offenses. They've finished in Football Outsiders' top 10 defenses four years in a row, regularly obliterating the Big Ten schools on their schedule.
The press-quarters design -- constant press coverage, aggressive blitzing and big safeties close to the line -- is brilliant. It takes away everything easy, daring teams to throw deep. The press-quarters defense pushed QBs to relieve the pressure by heaving fades that had little chance of doing damage.
The only question in the midst of this dominant run: what would happen if Michigan State faced the nation's better spread offenses? In 2014, that happened, and the Spartan rep didn't survive.
They drew eventual Rose Bowl winner Oregon, giving up 491 yards and 7.2 per play thanks to a huge day from Marcus Mariota. They took on the new challengers for Big Ten supremacy, Ohio State, which destroyed them thanks to 300 passing yards at 11.5 yards per.
These two set up the inevitable breakdown, when the scheme of Mark Dantonio and outgoing defensive coordinator Pat Narduzzi met its doom against Art Briles' Baylor in the Cotton Bowl.
Although the Spartans rode amazing offensive efficiency to a narrow victory, the defense was shredded for 603 passing yards, 11.6 per pass. And although Michigan State held Baylor to negative-20 rushing yards, one or two broken tackles could have been enough to give Baylor the win.
With Narduzzi moving on to the head job at Pittsburgh, Dantonio brought in linebackers coach Mark Snyder and tinkered, looking to shore up college football's formerly unbreakable defense.
Michigan State's struggles with Baylor were easy to predict for two simple reasons.
First, the Spartans' personnel was developed to stuff pro-style Big Ten offenses. Playing three true linebackers and a pair of big safeties is no way to counter the speed that the Bears put on the field.
The other problem is that the aggressive nature of the Spartans' defense anticipates opponents will try to beat it over the top and on the outside ... but not over the top and down the middle.
Against a pro-style team running play action, this defense is in solid shape:
The strongside linebacker (S) has run responsibilities, and the defense wants the strong safety ($) running down the alley to constrict the space the offense can work in. On play action, defenders look to fill aggressively against the run before covering the tight end (Y), but he's in such close proximity to the line and has so many bodies to navigate that it's hard for him to get open before defenders adjust.
On the other hand, against a spread alignment:
Play action will trigger aggressive pursuit by the outside linebacker (S) over the slot (Y) and the boundary safety ($) on the opposite edge. The result is a slot running free with multiple options for how to attack the deep safety (F).
Playing effective coverage in so much space is difficult for the best DBs. It's certain death for players who were chosen for their ability to decisively fill the alley. This was obvious before the game, but the Bears made it abundantly clear before their first drive ended.
The Bears only had 10 players on the field. But the structural flaws in the Spartan defense meant it didn't matter. Touchdown over the top and down the middle.
As Mississippi State defensive coordinator Manny Diaz says, "against play action spread teams, quarters becomes cover zero." Meaning, if your linebackers are sucked in by the fake run, there's no help for the safeties, who are left to play the slot receivers in man-to-man coverage from a terrible alignment.
In normal Michigan State quarters coverage, linebackers are responsible for disrupting the routes of the inside receivers, funneling them into spaces where the safeties can pick them up. Without the linebackers, the inside receivers get two-way options as to where they can run and will almost always beat the safeties.
This is why more teams are getting back to mixing in man-to-man blitzes against spread teams. If the offense can manipulate your linebackers into being unable to help your safeties, why not turn those linebackers loose on the QB?
The Spartans were pushed to abandon the defense that had carried them so far. They tried to play Cover 1 instead, in order to get their players in position to at least run with the Baylor receivers. MSU's lack of comfort was quickly evident.
While they hang on for dear life after this, relying on heavy blitzing and open field tackling, the Cotton Bowl put a punctuation mark on a statement made over and over again in 2014. The classic Michigan State defense is not built to handle modern spread offenses that create vertical stress with the slot receiver.
The challenge for the Spartans is protecting their safeties and preventing spread teams from ripping them apart in the middle of the field with option and play action concepts.
It seems they intend to stick with the press-quarters defense, running it 75 percent of the time, but mixing in other coverages to keep opponents from zeroing in on its weaknesses. Bringing more disguise is a strong idea. Most teams prefer to play both single-high and two-deep safety coverages.
But there is a cost in installing a new scheme that will affect how well the Spartans execute their base approach. If not this year, when the roster is loaded with upperclassmen, then perhaps in a future season.
What's more, playing this defense 75 percent of the time rather than 90, as they have in previous seasons, is still a large amount. It won't deter teams from zeroing in. Up-tempo teams will eventually suss out what the Spartans are doing and get to work.
What needs to happen, and most certainly is happening on the practice field, are tweaks to personnel and run-force responsibilities.
There's no need to stop pressing the corners or allowing the safeties to play close to the line. Safeties can still read plays while flat-footed before acting. What Michigan State needs is protection for the safeties from slot receivers and an emphasis on lighter defensive backs.
On an RPO (run/pass option) or play action play, linebackers (specifically S and W below) need to use their first few steps to fill passing windows, then rally to stop the run.
This is essentially the defense run by Ohio State in its title run, which borrowed from Michigan State but already included the tweaks to make it more spread-resistant.
This might result in fewer games in which the Spartans hold their opponents to negative rushing yards (though not necessarily, if they maintain their excellent six-man zone blitz strategies). But by keeping safeties close to the box, they should still be able to get hats to the ball before opponents can get much going on the ground.
With an absolutely loaded defensive line, the Spartans can afford to divert attention away from the run to ensure they don't give up 300 passing yards every time they play a good spread offense.
The Spartans must recruit more speed in order to feature LBs who can take steps to stop the pass before flying to the ballcarrier and safeties who can run with vertical routes.
Returning safety RJ Williamson has been looking to drop from 220 pounds to close to 200. Longtime cover safety Kurtis Drummond is being replaced by uber-athlete Montae Nicholson (who's still plenty big). If Jim Harbaugh stocks Michigan with big fullbacks and tight ends, then focusing on speed could be a concern, but the Spartans usually keep their linebackers free to attack just fine.
Finally, the Spartans should give their weakside end two-gap responsibilities, allowing the weakside linebacker to play the outside rather than having to drop away from the line to disrupt a pass route and then hurry to an interior gap. It seems Michigan State is planning to do that by featuring the 6'4, 300-pound Lawrence Thomas opposite former Big Ten Defensive Lineman of the Year Shilique Calhoun on run downs.
With these adjustments, the Spartans can continue to play their base the vast majority of the time, get their virtual nine-man fronts against the run and swarm even the most deadly spread teams.
Of course, this relies on finding corners who can play press coverage on the outside. Barring a surprising failure to develop those players, the Spartans have a chance to change their defense to handle the modern era. Hat tip to Briles for the poignant lesson.