Leistikow: Painful moments that shaped Iowa's transition to a 4-2-5 base defense

IOWA CITY, Ia. — With the clock winding under a minute to go and Iowa leading 17-14, Wisconsin quarterback Alex Hornibrook threw a spiraling football into the heart of the south end zone at Kinnick Stadium.

His wide receiver, A.J. Taylor, had juked into open space. The linebacker covering him, Nick Niemann, had fallen face-first to the ground. The safety too late to help, Amani Hooker, stood helplessly as the Badgers celebrated what would be the winning touchdown pass on a September Saturday night in Iowa City.

It marked one of the most painful moments of Iowa’s 2018 football season.

But that one snapshot served as the final straw of evidence for the Hawkeyes to move forward with a philosophy change — most likely for years to come.

MORE:The stats that shaped the 2018 Iowa football season

It was time to abandon the traditional 4-3 base defense — four defensive linemen, three linebackers — that served as the hallmark of the 20-year Kirk Ferentz era, dating to Norm Parker.

The time was now to transition to something Iowa coaches had discussed for more than two years. With a bye week ahead of an Oct. 6 game at Minnesota, Iowa would implement a 4-2-5 base defense, in which a fifth defensive back takes the place of the outside linebacker against most opponents.

The Hawkeyes stuck with that setup for their final eight games.

“I wish we would have done it earlier,” Iowa assistant defensive coordinator and linebackers coach Seth Wallace told the Register this week. “But sometimes, you live and learn.”

With the game on the line at Iowa, Wisconsin's offense adjusted to a “four-vertical” concept, in which four receivers are split wide and run downfield routes. The approach is designed to stress teams such as Iowa that rely on two deep zone defenders.

On the Badgers’ winning, 88-yard drive, Hornibrook completed all five of his pass attempts out of four-wide formations for 67 yards — including the 17-yard dagger to Taylor.

“Boy, that was glaring against Wisconsin,” Wallace said. “That’s kind of when the conversation was over with. 'OK, we’re going to get this done. We’re going to find a way to make it work.'”

Conversations about a switch were initiated after Iowa’s 2016 Big Ten Conference opener at Rutgers, Wallace revealed. In that game, the Hawkeyes — with Niemann’s older brother, Ben, as the outside linebacker — were victimized by that four-vertical concept. Iowa temporarily plugged in a third cornerback named Josh Jackson to help lock up that 14-7 win.

“Fortunately, we got out of that,” Wallace said.

It took until this past offseason for the talks to move from a simmer to a boil.

Even with the transfer of Brandon Snyder, the Hawkeyes were so deep at safety that one of their better young players, Geno Stone, was on the bench. Nick Niemann actually injured his knee at the end of that Wisconsin game, reinforcing the need for change.

Fortunately, Iowa's defense had the perfect guy who could serve as a fifth defensive back with cover skills while upholding traditional outside-linebacker duties of setting the edge against the run.

Amani Hooker.

“You wish those guys were easy to find,” Wallace said. “Unfortunately, they’re not."

At 6 feet and 210 pounds, Hooker became the Swiss Army knife for defensive coordinator Phil Parker. Hooker would be documented as a starting outside linebacker for Iowa’s final eight games, although he truly was a slot cornerback.

Meanwhile, Stone took over Hooker’s strong-safety role alongside fifth-year senior free safety Jake Gervase.

“A lot of the credit needs to be given to Jake Gervase. He’s really the signal-caller on the third level,” Wallace said. “… He was a big mentor to Geno when Geno took over that role, and it came natural to Hooker in some ways, because he’s a really special player.”

Iowa suddenly had a play-making defense. The Hawkeyes enter their Jan. 1 Outback Bowl matchup against Mississippi State tied for the national lead with 18 interceptions — 16 of them coming after the change to the 4-2-5.

Iowa really didn’t change its 4-3 philosophy as much as it changed personnel; it forced Hooker to be the only player to learn the intricacies of a new position. And he was great.

The true junior basically shut down dynamic Purdue receiver Rondale Moore. He tied Stone for the team lead with four interceptions. He finished second on the team in tackles.

And he was named the Big Ten’s defensive back of the year and a second-team all-American by many services.

No wonder he’s considering a jump to the NFL after the Outback Bowl — which, for the ninth straight Iowa game, will necessitate the 4-2-5 alignment.

Mississippi State runs “11” personnel (one back, one tight end) more than 70 percent of the time. Quarterback Nick Fitzgerald operates exclusively out of a shotgun formation, even for kneel-downs.

Hooker's return to school would be seismic for the 2019 Hawkeyes.

If he leaves? Iowa is flush with up-and-coming defensive backs. True freshman D.J. Johnson has been working as a slot corner (though he might be undersized), and incoming recruits Sebastian Castro and Dane Belton fit the mold, too.

With the large majority of Big Ten teams running single-back, single-tight end sets — Iowa, Wisconsin, Michigan and Michigan State are the exceptions — Iowa's 4-2-5 is here to stay, with a caveat.

The Hawkeyes maintain the flexibility to revert to using a third linebacker when offenses trot out heavier personnel groups.

“The (4-3 and 4-2-5) structures blend together. Our players (are) not having to think through this," Wallace explained. "It’s become pretty natural for us to go in and out of those personnel (groups) and not have to change the way that we term things."

Hawkeyes columnist Chad Leistikow has covered sports for 24 years with The Des Moines Register, USA TODAY and Iowa City Press-Citizen. Follow @ChadLeistikow on Twitter.