Xs and Os: Notre Dame's new defense a complicated overhaul

There are some offense-minded head coaches who are invested enough in their programs to recruit and demand excellence from the defensive side of the ball, even if they don't particularly care what the systems or strategies are for achieving it. Notre Dame's Brian Kelly seems to be such a coach.

Kelly's Irish offense is an oft-misunderstood system, primarily because he's known as being a spread offense guru. Consequently, people often falsely attribute traits to the Irish that don't accurately describe his approach.

It's more or less the classic football strategy of pounding it on the ground and then throwing it over their heads, only dressed up in the tactics of today. Notre Dame is a team that embraces the power run game, has become an NFL tight end pipeline, and typically uses spread sets with the aim of creating matchups or leverage for the vertical passing game. This is no dink-and-dunk, finesse offense.

That part of the Irish identity is well-established and will likely become more obvious to the greater college football world as Kelly is able to deploy strong-armed quarterbacks like Everett Golson, pounding running games, and vertical throws to big targets like promising sophomore Corey Robinson.

The Irish defensive identity is clearly not as well-established. It's about to be completely flipped, with NFL and college veteran Brian VanGorder taking over for the departed Bob Diaco, who left to be head coach at UConn.

The past

The Bob Diaco Irish defense used a classic 3-4 scheme with a bend-don't-break mentality.

The 2012 Irish D encapsulated what the approach should look like. The team relied mostly on its front seven to make plays while the defensive backs concentrated on staying in front of the ball. With defensive end Stephon Tuitt, "Irish Chocolate" nose tackle Louis Nix III, and Heisman finalist inside linebacker Manti Te'o all in the middle of the field, this tended to work out pretty well:

Te'o covered a lot of ground in the middle, with 113 tackles and seven interceptions, while the starting defensive line and rush linebacker (Prince Shembo) added 39.5 tackles for loss, including 27.5 sacks. The front worked with two-gap principles and some hybrid fronts that would allow players like Shembo or Sheldon Day to attack a single gap, rather than controlling blockers as Nix would.

Meanwhile, with solid tacklers like safety Zeke Motta able to play in deep alignments, teams were unable to land very many explosive plays, certainly not enough to offset the negative plays inflicted by a dominant front seven.

In 2013, the remaining inside linebackers struggled to show the same ability to plug gaps against the run game while impacting the passing game at 240-plus pounds, as Te'o had. The Irish also struggled without a strong nickel package and didn't have a great answer for teams that could put horizontal stress on their linebacker corps without dropping a safety down and spoiling their two-deep, bend-don't-break strategy.

Notre Dame slipped from eighth in defensive S&P to 48th in 2013 after losing Motta, defensive end Kapron Lewis-Moore, and Te'o from the starting lineup.

Against Oklahoma, a team with a grievously reduced offense that the Irish had squashed the previous year in Norman, Notre Dame found itself unable to handle speed and horizontal stress.

The Sooners effortlessly picked their way across the field with screens, quick passes, and runs while Notre Dame was unable to get the negative plays or pressure that had defined their defense the year prior.

With a young team heading into 2014, it again appeared likely that Notre Dame was going to be unable to replicate the 2012 formula.

The new plan

New defensive coordinator VanGorder's plan for deploying an Irish two-deep loaded with four- and five-star talents is completely different from Diaco's.

To begin with, the two-gap techniques along the front are gone, replaced with traditional single-gap techniques in 4-3 over and under fronts.

This is a bear front, with a nose tackle and two three-tech defensive tackles. It is aiming to fill interior gaps with big bodies who are maintaing their gaps and allowing linebackers to flow to the ball. The running back is forced to search horizontally for a crease to attack.

The Irish will probably be primarily an over front team, with Jarron Jones and Day asked to control the middle of the line.

Secondly, the VanGorder blitz package is pretty extensive. He was known for using a large variety of zone blitzes when he was with the Atlanta Falcons. Despite it being the spring game, VanGorder wasn't afraid to show the large role blitzes will have for Notre Dame in 2014. They even ran a delayed house blitz (eight pass rushers, three deep zone defenders):

They also mixed in several traditional zone blitzes:

With respect to quarterback Malik Zaire -- who had a great spring game and made a fantastic throw to his receiver, who had abused the corner -- that free-running middle linebacker doesn't pull up in a live game and probably gets a sack or impacts the throw.

Overall pressures like this revealed an understanding on the part of VanGorder of both how to overload protections and remain sound against modern offensive tactics.

The crucial details here:

• The defensive end to the field side of the formation plays through the right guard. He's working his way to the A-gap between the center and the guard in the event of a run, but he's getting there by attacking the guard, not the gap. The sam linebacker is attacking the edge and commanding the attention of the right tackle. Who's left to block the mike linebacker?
• No one. The OL successfully called for slide protection, which allows it to fan out against the edge blitz, but uses the extra man (the running back) to handle anything left over from the weak side. Because the end attacks and occupies the guard, the slide can't handle the stress, and the Irish D gets a three-on-two matchup that results in a free runner at the QB.
• The other important details are that they are matched up in coverage based on assignment, rather than strict zones. The dropping safety picks up the slot receiver, the will linebacker takes the flexed-out tight end, and the defensive end waits to pick up the No. 3 receiver, which is the running back.
• Everyone, except the boundary cornerback evidently, is being asked to matchup with a receiver whom he has the leverage and athletic ability to hang with. And there's a deep safety over the top.

One of the bigger differences between Diaco and VanGorder is a new focus on more aggressive coverages. To begin with, Notre Dame is making cover 1 a bigger part of the scheme.

The only real difference between these fire zones and cover 1 robber is that instead of bringing five pass rushers, the strong safety can drop down and "rob" routes over the middle of the field:

VanGorder has also mixed up these aggressive schemes with multiple versions of quarters (four deep defensive backs) and heavy use of Tampa 2 (more on that below).

While in the nickel package, VanGorder called a lot of cover 6, which is a type of quarters coverage that plays cover 2 to one side of the field and cover 4 to the other. It's becoming a popular call these days, because offenses will often tag the backside of their passing plays with routes meant to exploit favorable matchups between an isolated receiver and coverage that's been shaded to the passing strength.

Against cover 6, those weakside offensive concepts struggle. The corner and will linebacker are both free to be aggressive against quick routes, while the free safety plays over the top:

That isolated receiver on the boundary side isn't going to do much damage with a corner pressed up on him, plus help to the inside and help over the top.

This coverage is mostly vulnerable to the field side, as quick throws have space to operate and play-action carries the threat of getting the strong safety to bite down too hard and let someone get behind him. Notre Dame mitigates this in nickel by playing the nickelback in off coverage, allowing the strong safety to play flat-footed as he reads the tight end for a sign of a running play:

The outside receiver is covered man-to-man by the corner, while the nickelback potentially has the slot receiver in man coverage. The mike linebacker and strong safety ($) team up on the tight end. Teams are left with the option to throw easy, short routes to the field and hope to break tackles or get the slot receiver isolated deep against the nickelback, if they like that matchup.

The Irish can also mix things up by playing a quarters coverage that is stronger against the field side and vulnerable to matchups on the weak side.

Now the free safety shades over to play over the top of the tight end or third receiver, leaving the corner with no help against the boundary receiver. This requires both a very good boundary corner and a free safety who can read offenses well and has plenty of range. Alabama's Ha Ha Clinton-Dix is an example of the kind of safety who makes this scheme work.

If cover 1 and quarters didn't provide great enough diversity of base defenses, VanGorder has also installed the 2000's favorite defense, Tampa 2:

Tampa 2 has fallen out of favor for most teams except as a third-down package concept, as most teams would prefer to rely on quarters and safeties in the middle to stop modern passing games. However, if a team has a good mike linebacker who can make the deep middle drop, the corners know how to reroute receivers away from the trouble spots, and the team runs and tackles well, Tampa 2 is an exceptionally difficult coverage to beat with big plays.

All together, VanGorder has completely reversed the philosophy in South Bend. Instead of relying on overall simplicity and Diaco's werewolves, VanGorder has gone the more traditionally Catholic route: an intellectual approach with a different silver bullet for every beast that might rear its ugly maw. Van Helsing, you could say.

The Irish have schemes to answer for or attack every scheme an offense might present. They have bend-don't-break schemes and send-the-house options. They have everything in between to attack a protection, fragile QB, or offensive tendency.

But how will that work with what's on the roster?

The personnel (and potential problems)

Notre Dame has a very talented squad on defense. And they've already found a few obvious fits that would appear to match up with VanGorder's plans.

Perhaps the most surprising and potentially important fit is former walk-on linebacker Joe Schmidt. He's evidently been a guy who "can't come off the field" due to his mastery of the complex defense. Schmidt has the quickness and intelligence that is essential for a Tampa 2 mike linebacker, a position that has to quickly read for run or pass and potentially drop into the deep middle. It's a demanding yet thankless job, arguably the perfect role for a crafty walk-on with good athleticism. His leadership on the field may prove essential in 2014.

Former safety Matthias Farley has found a more comfortable home as a nickelback who can hold up in man coverage in cover 6 or cover 1. That would allow redshirt senior strong safety Austin Collinsworth to fulfill his calling as an aggressive run supporter who plays physical in the middle of the field.

Since Kelly took over the Irish program, they've slowly been upgrading the level of athleticism in the secondary. They now might have the players with corners like KeiVarae Russell and Cole Luke to be able to play some press coverage and be aggressive, rather than focusing on keeping the ball in front of them.

The defensive line will also likely benefit from the move to single-gap techniques, which will allow a player like Day to get into the backfield.

The big questions relating to this team's ceiling concern freakishly talented sophomore linebacker Jaylon Smith and the defense's ability to execute such myriad schemes.

Teams that rely heavily on quarters coverage often don't run a great deal of anything else (cover 1 is a valuable counterpart, because it has answers for problems quarters presents and overlaps with the same blitz techniques).

The heavy usage of Tampa 2 is what makes the Irish particularly interesting. Classically, teams that ran a lot of Tampa 2 relied on it as their main strategy. Every snap that Notre Dame spends practicing a rep-intensive scheme like Tampa 2 is a practice snap that's not spent guaranteeing that everyone understands their option responsibilities in a fire zone or spent practicing quarters pattern-reads vs. the spread.

Can Notre Dame's players handle the adjustment from one scheme to another that's both wildly different and complex? It's not the NFL, where players have the time and financial incentive to watch endless film and constantly meet with coaches on their assignments.

Equally important is how VanGorder utilizes Smith. Reflecting his different schematic install schedule methodologies is the fact that Notre Dame has apparently blitzed the former five-star with several different roles in the spring.

Diaco used him as the field-side outside linebacker, where his tremendous athleticism went from being a major plus to being a needed survival trait in order to cover the wide swathes of field for which he was responsible. In the new scheme he'll probably spend most of his time impersonating famous Tampa 2 will linebacker Derrick Brooks.

Smith's speed should allow him to play a Ryan Shazier eraser-type role in the Irish's Cover 2 defenses while making him a weapon in the blitz schemes. The question is when that ability and projection materializes.

SB Nation's own One Foot Down covered how some of Smith's fundamentals as a linebacker were lacking in the spring game and prevent him from maxing out his abilities. This is the sort of problem that can come up when a team's energies are spent learning how to discern werewolves from huskies, rather than nailing down fundamentals.

Fortunately for VanGorder, he's got at least two seasons with Smith and a young roster overall to mold and impress his thick playbook upon.

In the long run, whether or not the new Irish defense becomes the monster-hunting unit VanGorder envisions or if it becomes overwhelmed by the forces of darkness will largely depend on whether Notre Dame football players are as smart as their fans regularly insist they are. If so, Notre Dame will maintain its status as a contender in the Playoff era.

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