Exploring Michigan's defensive dominance in the age of Harbaugh

We are now halfway through the 2015 season, and over the past six weeks one thing has become increasingly clear: Michigan's 2015 defense is capital-e Elite.

This has been the step forward that fans have been waiting for ever since the defense made its last leap of improvement in 2011.  In Greg Mattison's first year running the defense it went from historically bad to a top-25 unit.  Over the next three years the defense hovered around that level of efficiency, trying to compensate for an offense and special teams unit that bled yardage and field position.  Michigan's defense under Brady Hoke was forever stout, but unable to carry all the team's water.

That is emphatically no longer the case; Michigan's defense has arrived.  While this column normally looks back at the last game, I figured that in light of last week's dominating performance, it might be worth our time to figure out just why Michigan's defense has been able to make the move from good to great.

Chaos, Personified

Before last week's game against Northwestern I spent quite a bit of time perusing our SBN sister site, Inside NU.  I thought they generally did a good job breaking down Michigan, and I liked a lot of the discussion I saw over there.  However, there was one glaring hole: no one was talking about Michigan's defensive line.  I read article after article, comment after comment, and all of it was the same.  There was a lot of talk about the secondaries and statistical similarities, but nothing about the biggest reason Michigan's defense has been a 40-ft buzzsaw this year: that motherf***ing defensive line.

I'm sorry about the swears, but bear with me, because any extended reflection on what Michigan's defensive line is and has done this year will make you want to throw on a leather jacket, grab a pack of Marlboros, and walk around the neighborhood intimidating old people and kids like a 50s greaser with an attitude problem.  That is a long way of saying that this defensive line is full of bad asses.

It all starts over the center, where Michigan has an incredible one-two punch at the nose tackle spot.  Ryan Glasgow is in his second year as a starter, and after emerging as an incredibly steady, high-energy Big Ten caliber starter a year ago, Glasgow has added the kind of slashing playmaking ability that the NT spot hasn't seen since Mike Martin was on campus.  When Glasgow goes to the bench, he is replaced by Mo Hurst, an even quicker penetrating force from the NT spot that has notched two sacks this year on three-man rushes.  These two have been consistently disruptive, either occupying double teams, slashing under blocks into the backfield, or collapsing the pocket on pass rushes.  Most importantly, both have consistently moved the point of attack on any given play from the line of scrimmage to somewhere in the backfield, throwing off running lanes, timing in the pass game, and protection schemes.

Of course, it doesn't stop there.  Michigan flanks these two with a rotating cast of 300-ish pound terrors at the 3-tech and SDE spots.  Willie Henry has played mostly at the SDE position this year, using his unnatural strength to punish double team blocks on the front side and set up stunts in pass rush.  Chris Wormley quickly emerged this year as a disruptive presence from the 3-tech spot, and his back up, Matt Godin, has nearly matched his impact.

All told, along the three non-hybrid defensive line positions, Michigan goes two-deep with disruptive players that are playing above average for Big Ten defensive linemen.  Because Michigan has been so consistently strong at the point of attack, and with little to no drop off between the starters and reserves, it has opened up a world of possibilities.  With four (including the WDE) defensive linemen against five offensive linemen, the ability of the defense to try different things is greatly expanded when three of those defensive linemen are capable of taking on and beating double blocks.  Right now Michigan has the 8th best defensive line havoc rate* in the nation at 5.4%, which is twice the national average.  Michigan's defensive strength radiates out from there, and in many ways, Michigan's defensive line dictates what all 18 other players on the field are able to do on any given play.  It has been the best unit on the field for either team in at least the last five games, and it would be in the discussion in the game against Utah.

Michigan's strong defense starts here.  The Wolverine front four is continually able to get pressure on the quarterback, blow up running lanes, and generally clog up the offense, freeing up the back seven to worry about other things.  Michigan doesn't even have an elite pass rusher at the WDE spot — something that most defenses of this caliber have — but it doesn't really require it given how effective the entire front four has been at coordinating pressure, maintaining rush lane responsibility, and running effective stunts.

Michigan's line has created chaos up front for opposing offenses all year, and that sets the table for everything else this defense does.

*(A metric judging a defense by its ability to create TFLs, pass break ups, and forced fumbles on a play by play basis)

On Lockdown

On the checklist of things great defenses have, the next thing down the list from terrifying defensive linemen is "corner who fits comfortably in all types of wide receivers' back pocket".  That corner is Jourdan Lewis, and it is getting harder and harder to overlook his individual brilliance.

Last year Lewis jumped into the starting lineup after an injury to Raymon Taylor, and Lewis never relinquished the job, showing himself more than comfortable in the press man pass defense the coaching staff wanted to run.  Of course, he was the only one comfortable in it, and if you know anything about press man coverage defense, you know that having just one corner comfortable in that scheme will portend bad things.

This year, Michigan has been able to commit to its hyper-aggressive defensive approach in the secondary, and Lewis has been deployed as the ultimate trump card in the passing game.  He started the first few games playing on the outside, but was moved inside on nickel packages against BYU and Maryland to match his speed and quickness against dynamic slot receivers.  Lewis has the perfect mix of masterful technique and jaw-dropping athleticism, and he has put it all together for an all-American level six week stretch so far this season, capped with a pick-six last week against Northwestern.  According to Pro Football Focus, Lewis has been targeted 34 times this season, allowing only 11 completions for 67 yards — not bad when you consider he has almost as many pass breakups (8) and interceptions (2) as completions allowed.

Opposite Lewis, Michigan has also benefited from the improvement of Channing Stribling into a starting Big Ten caliber corner.  Stribling played a bit part as a freshman, most notably as a stand-in for the photos of Allen Robinson's highlight-reel catch.  He wasn't seen much last season, but emerged in camp as one of the most improved players, and has proven to be a solid player in the four games he has played.  Michigan also moved 6'4 speedster Jeremy Clark from safety to corner, and that move has paid off in spades as Clark can use his size and athleticism more effectively in coverage on the outside.

With three effective corners, Michigan can play a lot of aggressive man coverage which 1) throws off timing between quarterback and receivers, 2) makes it harder to run receiver screens in the flats, and 3) closes windows on quick passes allowing the defensive line more time to mount a pass rush.

Taken together, that gives Michigan a punishing defensive line that is effective at pushing the point of attack into the backfield and collapsing pockets, coupled with a secondary that effectively plays aggressive man coverage and is led by a lockdown corner.  That all sounds pretty good so far.

Clean Up Crew

One of the most shocking defensive stats comes from the BYU game, and it isn't necessarily what you would think.  Michigan spent most of the day in dime coverage, using six defensive backs to neutralize BYU's passing attack.  That left Desmond Morgan as the only linebacker to play, and he played pretty much the entire game on defense.  He also finished the game with two tackles.

Michigan's best, most reliable linebacker was called on to finish a play twice.

And that has been one of the biggest effects of Michigan's aggression and skill in coverage and along the line: it opens up everyone else's job and makes it easier.  Michigan's starting linebackers this year are both averaging just six tackles per game.  Michigan's safeties are rarely ever mentioned by name during games.  Why?  They just aren't heavily needed.  In fact, most of the time Michigan plays with its safeties well over ten yards off the line of scrimmage to help keep a cap on plays over the top.  Why does Michigan have the freedom to put two defenders in the parking lot?  Because those safeties aren't needed for run support.

The Wolverine run defense currently ranks first nationally in opponent adjusted line yards*.  Running backs just aren't getting to the second level against this defense.  Michigan is also second nationally in plays allowed of 20-plus yards with only nine (just one play was 30-plus yards).

In summation, Michigan's defensive line and coverage strength is so great, that it does the majority of the work for the defense, allowing linebackers and safeties to flow freely in run support and play conservative pass coverage over the top.  Those two units are so good that they shrink the window of success to such a degree that it is easier for the linebackers and safeties to slam it shut.  Michigan's first line of defense is so good that it has rendered the second line of defense largely irrelevant on a lot of plays.  That's how a four-year starter at linebacker ends up with two tackles in a shutout in which he played every snap.  Its hard to make plays when everyone else beats you to them.

*(A measure of how a run offense does based on weighting the first four yards of a carry more heavily than those that come after it, in hopes of figuring out how well the line opens holes for a back without the line getting as much credit for yards gained down the field).

What Does This Mean Going Forward?

Pain.  A lot of it.

The Big Ten doesn't currently boast the most efficient offenses in the nation.  Minnesota and Penn State have looked like tire fires, Indiana lost its starting quarterback and his backup for an indeterminate period of time, and Rutgers is still Rutgers.  If the last four games have taught us anything it is that a shutout is certainly on the table at least four more times this year.

The big questions bookend those games.  Can Michigan shut down Michigan State and Ohio State?  Neither offense has played up to its potential this year, but both teams have the mix of offensive line, talent at quarterback, and athleticism at the skill positions to give the Wolverine defense trouble.  Those two games will test Michigan's scheme and its athletes.  However, after six weeks of watching this defense play, it is easier and easier to envision it winning its battles against these offenses than it has been in many years.