Roots of Husker coordinator Bob Diaco’s 3-4 defense trace back to longtime coach Al Groh

Roots of Husker coordinator Bob Diaco’s 3-4 defense trace back to longtime coach Al Groh
World-Herald News Service

LINCOLN — When Al Groh gets a request from an inquiring mind, he’s happy to share what he knows. And when it comes to the 3-4 defense, Groh knows a lot.

The former NFL and college coach refined the scheme with and learned from some of football’s best defensive minds — Bill Parcells and Bill Belichick. He worked alongside a dominant college coach, Nick Saban, who also runs the same version of the defense. In nine seasons as Virginia’s coach, Groh’s team ranked in the top 40 nationally in scoring defense six times, including three in the top 25.

Of most interest to Nebraska fans, Groh is the guy who downloaded much of what he knows about the 3-4 scheme into defensive coordinator Bob Diaco.

Diaco worked at Virginia for Groh from 2006 through 2008.

At his introductory press conference at NU, Diaco referenced Groh, who worked for four NFL teams from 1989 to 2000 — the Giants, Browns, Patriots and Jets — and coached some of the league’s best defensive players, including Lawrence Taylor and Willie McGinest.

Learning under Groh “was a spectacular education,” Diaco said. “What a great teacher.”

When Diaco hired a defensive coordinator at Connecticut, he picked a Groh assistant he’d met at Virginia — Anthony Poindexter, who’s now at Purdue.

While Diaco has put his own flavor on his defense, many of the principles are similar, and so is the language.

Diaco talks about his scheme being rooted in “block destruction” at the line of scrimmage. Groh calls the scheme a “beat the blocks” defense and likens it to the center of a boxing ring.

Virginia’s coach from 2001 to 2009 talks about the inside linebackers in his 3-4 needing to be “physical, downhill” players. Nebraska linebackers coach Trent Bray preaches the same thing daily in practice — “forward, forward, forward.”

“They’ve got to be downhill players,” Bray said. “They’ve got to be solid and tough against the run. That’s No. 1.”

And while any defense can be effective, Groh believes in the 3-4 because of its versatility, flexibility and, at least in college, how it can throw off offensive linemen who aren’t used to it. Nebraska’s offensive linemen can attest after struggling against the 3-4 scheme run by Wisconsin and even Purdue for several years.

Coach Mike Riley — who once ran the 3-4 in the Canadian Football League — is a believer, too. After more than a decade in the 4-3, he wanted to switch to the 3-4 because of its versatility.

“You have a great variety of blitzes you can use out of the 3-4,” Riley said at Diaco’s introductory press conference. He added that, because an offense doesn’t always know where a fourth pass-rusher is coming from, it’s not so easy for the running back to go out for a pass.

In the middle of this scheme change is Diaco, a trim man who is a whirling dervish at practice. Dressed in all gray, Diaco bolts from place to place, teaching loudly and in detail. At times, even before the play is over, Diaco so quickly knows what happened that he’s bounding toward a player either to praise or critique him.

It’s exactly the guy Groh remembers.

“Bob was very good,” Groh said. “Very highly organized. Very purposeful. Great attention to detail.”

So was Virginia’s defense when Diaco was there. The Cavaliers never gave up more than an average of 21.7 points or 333.3 yards in any season. In 2006, UVA gave up 17.8 points and 289.5 yards per game.

Groh’s 3-4 scheme is more of a two-gap system, he said, similar to the one used by Parcells, Belichick and Saban, who worked under Belichick when the latter was coach of the Browns. The two-gap moniker essentially means that defensive linemen, like a nose tackle, are responsible for minding two run gaps, or the gap on either side of their blocker, instead of shooting into one gap. The one-gap 3-4, which Groh said is used by many NFL defensive coordinators, including Wade Phillips — is much more aggressive.

In a 3-4, since the three down linemen are sometimes — not always — across from an offensive lineman, the two-gap approach is common. That doesn’t mean it’s easy.

“It’s a real physical style of play,” said Groh, who serves as a radio analyst for Westwood One Sports. “There’s no running away, there’s no rope-a-dope when you’re playing a two-gap.”

Linemen, Groh said, have to be “explosive, powerful and laterally quick.” The nose tackle is especially important, as he could face some tough double-teams.

Linebackers in the scheme fill different roles. The inside linebackers — for Nebraska, Chris Weber and Dedrick Young are the frontrunners for the role — are there to plug up running lanes. In a one-gap 3-4, linebackers have a gap and attack it. In a two-gap, they read the linemen in front of them and fill accordingly. The goal is to build a wall so ballcarriers struggle to find daylight.

“And good solid walls don’t have any holes in them,” Groh said.

Bray, and occasionally Diaco, exhorts the inside linebackers to be aggressive in moving forward. In the 4-3 defense coordinated by Mark Banker, Bray said the linebackers were more “scrape players.”

“We had four guys taking up blocks so you could play with a little bit lighter kid who could get over the top and shoot a gap,” Bray said. “Now we’re in a couple different fronts and we need plug players.”

The outside linebackers “probably have the most diverse assignments” of any player on the defense, Groh said. They also have to be the most dynamic athletes. They’re able to drop into pass coverage if necessary. They’re able to rush the passer standing up or with a hand on the ground. They’re also able to set the edge on a running play.

“They’re your 3, 4, 5 hitters — your home run hitters,” Groh said.

Among the Huskers at the position, senior Marcus Newby — a stand-up defensive end in 2014 before becoming an outside linebacker in 2015 and 2016 — has the most experience.

“Marcus can do a lot of different things for the team,” Diaco said. “He becomes a tool that can do a lot of things, and his skill set allows him to play athletically out on the perimeter a bit. And he doesn’t really have any limitations from jobs for us.”

Other outside linebackers are Alex Davis and Sedrick King, who were once defensive ends, and Luke Gifford, a Lincoln Southeast graduate who was a safety coming out of high school, bulked up to become a 4-3 outside linebacker and now plays 3-4 outside linebacker.

Though every defense needs speedy players, the 3-4 also has sizable guys in the front seven, Groh said. It’s not uncommon for inside linebackers to be north of 240 pounds, as long as they can move. Most of Nebraska’s defensive linemen gained weight in winter conditioning. One only need look at Nebraska’s prized defensive tackle recruit — 6-foot-2, 310-pound Damion Daniels, who’s still 17 — to know where the Huskers are headed in terms of building bigger bodies.

“This is a game for big people, and size is a tool a guy brings to the fray,” Groh said. He added that he thinks Nebraska probably has the players to do the job.

Nebraska’s secondary schemes are likely to change, too.

NU offensive coaches have reported seeing a variety of coverage — well disguised, too — from Diaco’s defense already. Banker preferred to start with his quarters system and build from there, while Diaco seems to have a deeper playbook.

Like Groh’s system, Diaco’s 3-4 defense has consistently worked. In four years at Notre Dame, Diaco never had a scoring defense rated worse than 27th nationally. At Connecticut, the talent pool was much different, but Diaco’s 2015 group ranked 15th nationally in scoring defense.

Since joining the Big Ten, Nebraska has never ranked higher than 33rd nationally in scoring defense.

That was the 2016 defense. Banker got fired for it.

Sixty-two points against Ohio State, 40 points against Iowa, and 38 in the bowl game,” Banker said after his mid-January firing. “Big plays. All those things. That’s what people don’t like.”

Regardless of the defense Diaco runs, that’s what he was hired to change.

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