For the last three years the Michigan State Spartans have had a brilliant run of success in the Big 10. They won the Big 10 in 2013 and 2015 and finished 11-2 in 2014 while falling just behind Ohio State for the league title. Over that same period of time, Michigan State has gone 2-1 in their postseason games with victories in the Rose Bowl over Stanford (2013) and in the Cotton Bowl over Baylor (2014).
However, in those three bowl games the opposing QB has averaged the following numbers against the Spartan pass defense: 33 pass attempts, 326 yards, 9.8 yards per attempt, and a 2-1 TD-INT rate. These numbers aren't entirely skewed by Bryce Petty's big day either as Kevin Hogan was fairly effective against 2013's "no-fly zone" in only 18 attempts in the Rose Bowl, throwing for 7.9 yards per attempt.
At some point it has to be asked if Michigan State's defense is somewhat gimmicky in nature, designed to allow them to gang up on teams that prefer to run the ball but simply ill-equipped to stop a spread passing attack. If the answer is yes then the follow up question becomes, can they ever win a national title playing defense this way?
Let's start by diving into the problems with Michigan State's pass defense, which were highlighted for us by Lane Kiffin in the playoff semi-final where Alabama destroyed the Spartans 38-0.
Pressuring the stress points
In my preview of Michigan State vs Alabama I went over the two main coverages for the Spartans and their stress points, noting that their aggressive, six-man zone blitz schemes were pretty solid at protecting their base defense save for in the flats, where both systems are potentially vulnerable.
As a refresher, let's look at their two coverages with their varying stress points. Here's their cover 4 scheme:
Before a Spartan fan interrupts to note that Michigan State's press-quarters coverages work just fine when they have great cornerbacks, let me note that the softest part of the coverage is actually what's asked of the free safety in covering a slot receiver on RPOs or play-action.
Since that sam linebacker is going to charge at the line of scrimmage on any run action from the offense, that leaves the slot receiver with a two-way go and a lot of space to work against that free safety. Essentially, that safety is being asked to play man coverage 10 yards off the receiver. Even for a good athlete like Montae Nicholson or Demetrious Cox that's exceptionally hard.
Of course, if Sparty is blitzing then they have deep coverage to help and two seam-droppers to help protect the deep safety and the QB probably has little time to find the slot receiver running a deep route. Here's their favorite zone blitz:
You'll notice that in either coverage the Spartans are still vulnerable out wide and in the flats. Here's one way that Kiffin set up his offense to attack cover 4 while still having a way to attack the defense if they faced a zone blitz:
At the line it's a play-action play with max protection as the running back and tight end both stay in to help block and allow time for the deep routes to develop.
Alabama's freshman burner, Calvin Ridley is lined up in the slot and his seam route is the focus of the play design. He's basically running up the seam against free safety Demetrious Cox and running to open grass wherever he can find it. Since Cox is starting the play in off coverage and Ridley has a two-way go against him, it becomes very simple for Ridley to just run past him.
The outside receivers are running deep routes but they have comeback options in the event that the Sparty corners are playing off. That means that Michigan State is running one of their blitzes, Coker should be able to have a release valve throwing a comeback to either of them. Alabama made it a point throughout the game to include some comeback options on the outside to allow Coker to safely get the ball out in the event of a big zone blitz from the Spartans.
The Tide could have run this play several times and ripped the Spartans apart, but they didn't, nor did they really need to. As it happens, they had a few other passing plays drawn up especially for Michigan State.
Here's one they ran against Michigan State after pinpointing a flaw in how the Spartans tend to respond to a trips formation with a TE lined up opposite the three receivers.
The problem for Michigan State this time is that they like to roll their safeties over to the trips side against spread formations and play the weakside in man coverage. Against most tight ends and running backs perhaps this would turn out okay, but Alabama had Kenyan Drake and O.J. Howard in the game.
What really burned Sparty here is that the cornerback is playing the TE in man coverage but he has outside leverage, the DE doesn't jam the TE at the line, the linebacker has to cross in front of him, and most importantly there's zero help inside because both the weakside linebacker is chasing the RB in man coverage and the strong safety and middle linebacker are both shaded to the trips side.
Alabama really got after Michigan State by throwing to the slot and to the TE and Howard finished the day with 59 yards on just three catches. Again, it could have been much worse if Alabama had needed more offense.
There were also repeated instances where Alabama was able to pick up Michigan State's six man, zone blitzes and Coker knew exactly where to go with the ball and had receivers open outside the numbers in front of the corners.
Finally, even Michigan State's aggressive approach to defending the run element of RPOs was exposed by Alabama, despite often inaccurate throws by Coker that failed to lead his receiver.
Lane Kiffin can be good at attacking opposing teams, but Alabama is pretty simple with their passing game and Jacob Coker is a flawed trigger-man even if he is surrounded by great talent. Michigan State simply got beat because their scheme is poorly equipped to handle spread passing attacks.
So why does it work in the Big 10?
The Big 10 doesn't really have any good spread passing teams currently. Ohio State ripped the Spartans apart throwing the ball in 2014 but in 2015 they couldn't execute a hitch route to save their lives. Harbaugh's Michigan isn't quite there yet at the QB position and were starting a transfer who'd never played in the system before. Tommy Armstrong is hardly a pocket passer yet he burned the Spartans this year for 320 yards on 33 attempts.
There simply aren't many spread teams in the Big 10 and what ones there are typically orient more around the running game than trying to throw the ball. The Spartans were solid in their re-match against Oregon and Vernon Adams, but it was the QB's second game as a Duck in an offense he'd just learned that fall.
There simply aren't many teams in the Big 10 that are oriented around throwing the football from spread passing alignments. If there were, it would be clear that it isn't that difficult to design plays that can punish the Spartans for playing the run so aggressively in coverage and frequently leaving their safeties and corners in difficult spots.
Name a team in the Big 10 that's built to attack vertically with their slot receiver to attack the flats in the passing game and you'll have your answer for why the Spartans' aggressive approach doesn't get them into too much trouble until their bowl games.
What does this mean for the future of Michigan State football?
I expected the Spartans to adjust their approach after Baylor took it to them in the Cotton bowl last year but that didn't really happen outside of the Spartans using more off coverage rather than press outside, and that was more likely a response to no longer having NFL corners than getting exposed by Baylor.
Optimism around that program is high right now but it's very possible that their window for Big 10 dominance is over. The more engrained Harbaugh and his passing attack gets in Ann Arbor the more vulnerable the Spartans will be to their in-state rival. Also, the more that spread passing attacks work their way north of the Mason-Dixon line the more vulnerable Sparty will be.
The question will then become how they can adjust to maintain their aggressive approach without getting ripped by opposing passing games. Part of that solution will have to include either being less aggressive with their space-backer/nickel player or else using one of their best cover athletes at free safety. Since they already moved former boundary corner Demetrious Cox to that position there's not much else they can do there save for play the space-backer less aggressively.
Another part of the solution will probably have to be more variety with their coverages so that opponents aren't able to attack them so easily. The TCU Horned Frogs play similar coverages, and at times get into similar trouble, but they also mix up when the safeties are coming downhill and when they are free to drop deep so that they aren't victimized as easily by track star slot receivers. Spartan fans will no doubt say that they just need to develop some great cornerbacks again but that's much easier said than done and wouldn't address the inherent weakness in their scheme anyways.
WIth the direction the game is going there's no chance of the Spartans winning a playoff with a scheme that's so vulnerable to good spread passing attacks. It's also likely that their window for dominating the Big 10 will also close as Harbaugh gets Michigan going, Riley and Chryst repair the passing games at Nebraska and Wisconsin, and Ohio State adjusts after a disappointing 2015.
Mark Dantonio has been a brilliant coach but these next few years will say a lot about whether he's flexible enough to keep Sparty going when the rest of the league adjusts or if the best days of his era are behind them.