Why TCU odd stack defense presents unique challenges for Georgia in championship

Follow Georgia vs TCU College Football National Championship Game live.

Delaware defensive coordinator Manny Rojas was halfway through his New Year’s Eve meal last Saturday when his phone kept buzzing with texts from his staff imploring him to turn on the Fiesta Bowl.

TCU is running an odd stack and is kicking the crap out of Michigan. You have to watch this.

So, Rojas choked down the rest of his prime rib and hustled back home for the second half to witness the Horned Frogs holding Michigan to under 200 yards rushing en route to securing a spot in Monday’s national championship game against Georgia.

“Our staff spent the entire weekend examining that film,” Rojas said. “And goodness gracious, it opened my eyes to a game plan on how to attack these bigger, heavier run teams.”

To the casual observer, TCU’s Fiesta Bowl victory was the next big upset in the topsy-turvy landscape of college football. But to odd stack coaches like Rojas, it was more than that. It was a unified rallying cry and public verification on a national stage that their system can hang with the big boys, particularly in the run game.

And Rojas wasn’t the only odd stack coach in his glory last weekend. For years, the odd stack has been given a bad rap for being a “soft structure” because there are more skill defenders on the field than defensive linemen.

“People assume because there is one less defensive lineman that has to be blocked that offenses are going to maul you at the point of attack, and it doesn’t always work that way,” Rojas said.

Former Ole Miss head coach Joe Lee Dunn was credited with creating the odd stack structure in the 1990s as defensive coordinator at Memphis. Also termed the 3-3-5, its structure is based on the alignment of three down linemen, three stacked linebackers and five defensive backs. Teams that use it rely more on speed (by having fewer lineman types) than strength to pressure offenses, often disrupting blocking schemes in the run game and pressuring the quarterback in the passing game.

While many teams — like Dunn’s operation at Memphis and Syracuse defensive coordinator Rocky Long’s teams at New Mexico and San Diego State — have had periods of success, perpetual knocks on the odd stack system have been attached to it for years.

They are, in no particular order:

Quicker personnel can’t handle downhill run game

Three down linemen can’t defend interior gaps as well as four down

Linebackers and safeties struggle against overload (tight end) formations

But coaches in the 2.0 version of the odd stack, most notably TCU defensive coordinator Joe Gillespie, have found ways to mask these structural weaknesses. There have been several odd stack outfits inside the top 20 in total defense this season, including Iowa State and NC State at the FBS level and Austin Peay and Rojas’ Delaware unit at the FCS level.

To be clear, the TCU defense isn’t exactly among the nation’s elite in any particular category. In fact, it’s outside the top 50 in most, including total defense (78th), rushing defense (70th), yards per play (64th) and points allowed (64th). But make no mistake: Last weekend’s effort was a monumental win — not just for the TCU program under the first-year coordinator Gillespie, but for the odd stack system.

There are two schools of thought coaches have when operating out of the odd stack: either throw the kitchen sink at the offense by using post-snap pressure (as Dunn did) or play the pre-snap numbers game and beat them at the point of attack. Gillespie chooses the latter, which is making even more of an impression among odd stack disciples.

“I think many people think of odd stack and immediately think of a blitz-happy type scheme,” said Ryan Lucchesi from Muskego High School (Wis.), one of the top prep programs in the Midwest. “This isn’t the case for our operation and doesn’t appear to be TCU’s style of attack.”

Gillespie’s operation is configured as a field and boundary defense, meaning that defenders are split into field and boundary alignments, traveling together. There are essentially three foundations on which the TCU defense is built:

Put strength to the boundary

Put speed to the field

Configure a versatility of different looks

Players can play fast because the system is so simple.

Strength to the boundary

Gillespie aligns his bulk to the field, and it’s anchored by boundary defensive end Dylan Horton. At 6 feet 4, 275 pounds, Horton moves like a safety. That’s because he was one at New Mexico before transferring in 2019. He has a non-stop motor in getting after the quarterback, leading to a team-high 10.5 sacks. And Gillespie knows Horton is strong enough to hold the point in play-side runs, which is why he aligns him in the B gap — an interior gap mainly reserved for defensive tackles.

He’s also quick enough to play the C gap, where he can work inside-out on ball carriers.

In the clip below against Michigan, he extends and sheds the block of offensive tackle Karsen Barnhart, making a stop at the line of scrimmage.

And when offenses try to add an additional run surface to the boundary with a tight end, it’s still no match for Horton, who has the strength to split double teams at the point of attack.

Horton’s counterpart to the boundary is Navy transfer Johnny Hodges (81 tackles), the Big 12 Defensive Newcomer of the Year. Hodges plays the boundary outside linebacker position, the same spot where Tulsa’s Zaven Collins blossomed under Gillespie and won the Nagurski Trophy, Lombardi Award and Bednarik Award in 2020.

At 6-2, 240, Hodges is not a typical weakside linebacker. He’s much thicker and has the hand strength to play up on the line of scrimmage in an edge technique against thicker tight ends.

“While he’s not completely on the line of scrimmage, the offense must account for him,” said former Austin Peay defensive coordinator Chris Kappas, who runs the same system. “This semi-mugged alignment still allows him to read out of the gap vs. pullers, but also gives him space to attack quickly and plug his gap.”

In the clip below, he can set the edge quickly and get the ball turned back inside to Horton.

He’s also strong enough to play in what coaches call a “30” technique, a true inside backer alignment in a 4-3, as he did against Michigan.

He is a “knockback” tackler in the run game and had his best outing against Texas, earning Big 12 Defensive Player of the Week honors. Here, he jacks up Longhorns running back Bijan Robinson for a loss:

Speed to the field

Gillespie’s unit is built on speed, and most of those defenders align to the wide side of the field. The stack defense is built to push the ball to the perimeter so defenders can pursue from the inside out. And at TCU, field support is usually shored up by two phenomenal athletes, field-side outside linebacker Dee Winters (No. 13) and nickel Bud Clark (No. 5), who are extremely active against the perimeter run game, often boxing the ball back to one another.

Winters is a senior All-Big 12 pick who was a receiver in high school. A violent tackler (14.5 TFLs), he has the change-of-direction speed to react quickly even when he gets caught inside, as he does in the clip below against Colorado.

And against heavier run surface teams like Michigan and Baylor, Winters was able to play up on the line of scrimmage and chase things down from the backside.

Clark, a sophomore, may be one of the most athletic safeties in the country. At 6-2, 190, he has the physicality to play at or near the line of scrimmage in the run game. Clark has 40 tackles, mainly on perimeter run concepts.

The clip below is a good example of how Clark and Winters play off each other. Oklahoma utilizes a pin-and-pull concept run to the field. Winters “wrong arms” the first pulling guard, pushing the ball back inside to Clark, who makes a terrific one-on-one tackle at the line of scrimmage on running back Tawee Walker.

And last week against Michigan, he made several stops at or near the line of scrimmage coming from depth. In the clip below, Winters again boxes the ball back inside to him, where he undercuts Michigan running back Donovan Edwards for a 3-yard gain on first down.

Versatility of defensive looks

It’s a common adage in coaching that skill players are smarter than linemen (not my words as a former defensive end), but defensive backs have more of an innate ability to understand coverage and run fits because they play off the ball. Because of this, the stack defense can mutate into a variety of front and coverage structures without subbing personnel. It has worked in Gillespie’s favor because an offense can’t always predict where the extra run-fitter is coming from.

“You’re going to get a numbers advantage one way or another,” Rojas said. “You just don’t know where that extra run-fitter is coming from.”

Lately, Gillespie has had a knack for getting his players in the right spot and doing so without bringing pressure. He’s credited with blitzing on a national-low 13.8 percent of snaps, according to Pro Football Focus. Instead, he’ll equate numbers by defensive structure at the first and second levels. The Horned Frogs are primarily a man coverage team, and with two first-team All-Big 12 corners in Tre’Vius Hodges-Tomlinson and Josh Newton, why wouldn’t they be? They have a combined completion percentage rate against them of 34 percent and can press receivers on any given snap.

So, Gillespie prefers to adjust by structure first, outnumbering offenses in the box to stop the run. Quite simply, offensive formation dictates the support structure, and having two exceptional athletes at the corner position allows him to put a premium on stopping the run.

First-level surface presentations

Most traditional odd stack defenses operate out of a 4i-0-4i alignment at the line of scrimmage. This means there is a nose head up on the center, with two defensive ends aligned inside the offensive tackles.

While this may be a Day 1 starting point for TCU, Gillespie will continually alter these first-level alignments quite subtly, either pre-snap or post-snap. It’s called changing the “picture” of the front. He’ll do so to protect those interior gaps that are so coveted by offenses when attacking an odd stack in the run game.

For example, because Horton is usually a B gap player to the boundary, Gillespie will use his field defensive ends (Caleb Fox and George Ellis) as two-gap players away from him. They may line up outside the tackle (as C gap defenders pre-snap) but will instantaneously work into the B gap against any zone run game. Mercer defensive coordinator Joel Taylor — an odd stack adherent — calls it a “knockback” technique, which forces the ball to the perimeter where skill defenders can make tackles.

In the clip below against Oklahoma, Ellis maintains the B gap, while Winters plays over the top. Ellis eventually makes the play by taking on the block.

“Those subtle changes in the surface give an offense challenges,” said Kansas State defensive pass game coordinator Van Malone, who runs a similar system. “When preparing against a four-down front, the offensive line coach wants to have consistency in his pictures. You don’t get that with the stack.”

And if Gillespie doesn’t change the picture post-snap, he’ll change it pre-snap. The Horned Frogs will find a way to play with four defenders at the line of scrimmage but often alter who that player will be, which is the benefit of the defense.

Gillespie calls it the “fourth” rusher and it manifests in several ways. He’s had the most success with using Winters as the fourth rusher to the field. Winters will walk up on the line of scrimmage, which he has done on 36 percent of snaps this season.

In the clip below, he comes free off the edge for an easy sack against SMU — one of 7.5 this season, second only to Horton.

Another variation that Gillespie has used is the bear front, most commonly against Michigan last week. This presentation puts both defensive ends in the B gap outside the guards, while two linebacker types walk up on the edges.

The bear front essentially eliminates offensive double teams in gap runs.

“This prevents the tight end from climbing to the inside backers and still makes the offensive guard block the nose before climbing up to the second level,” Kappas said.

TCU also operated out of a traditional under front on 89 snaps this season, mainly against heavy personnel teams like Baylor and Michigan. This puts the defensive end in the C gap against a tight end surface and was another way for Gillespie to close gaps at the line of scrimmage when an offense tries to create them.

Second-level presentations

The Horned Frogs play with five defensive backs on more than 96 percent of snaps — second only to Tennessee. This means they won’t sub in an additional defensive lineman against heavier personnel. They will adjust with their secondary defenders. Most can play at or near the line of scrimmage, particularly a linebacker corps that averages 6-2, 237 pounds.

Gillespie will revert to his philosophy by outnumbering offenses at the point of attack to try to win in the box. He can do so by changing which second- or third-level defender is the extra run-fitter. Last week, it was about walking down a high safety — mainly Clark — to Michigan’s heavier run surfaces, including wings and tight ends.

The presentation resembled more of a 3-5-3 look (with eight box defenders) instead of the traditional 3-3-5 look with six box defenders.

Instead of going to four down or spinning a safety, they are committing an eight-man fit into the run by keeping their three linebackers in the box closer to the ball and using those two safeties as hard edges to fit the run. This helps match numbers at the point of attack and is a good wrinkle to fix a perceived weakness of the odd stack’s soft edge.

“You go from 3-3-5 to 3-5-3 within one snap to another,” Rojas said. “It’s the same teaching, but to an offense, it looks completely different. You don’t see that often.”

In the clip below, the Wolverines run a power scheme to the heavy surface. How TCU’s linebackers and safeties attack the line of scrimmage forces double teams off down defenders. Winters can take on the lead block of the fullback and still get involved in the tackle with help from safety Millard Bradford

And even when Michigan tried to work opposite the formation strength, Ballard was physical enough to body up Edward in an in-the-hole tackle for a 4-yard gain.

Conclusion

There is no doubt that this TCU defense will face another stiff challenge in the run game, as Georgia enters Monday night averaging a shade over 200 yards per game on the ground. But if Gillespie’s unit finds a way to take the ball out of running back Kenny McIntosh’s hands and make the Dawgs one-dimensional — as they did against Michigan — TCU’s offense is balanced enough to make this quite a game.

(Top photo: Joe Camporeale / USA Today)

ncG1vNJzZmismJqutbTLnquim16YvK57k2ltamhlbnxzfJFsZmlpX2WDcMDCrmScp5GYtaa%2FjKyaoZ2dmnqosc6rnqKZXZu8sMDBmqOlZw%3D%3D