Kirk Ferentz knows the Michigan defense has changed.

The Wolverines will come to Kinnick Stadium on Saturday with one of college football’s most improved defenses.

Michigan finished 110th in total defense in 2010. This season, under new head coach Brady Hoke — and, more importantly, defensive coordinator Greg Mattison — the Maize and Blue’s defensive unit is ranked No. 28.

Add in the fact Michigan has forced numerous turnovers in seven of the team’s eight games and rank first in the nation in red-zone defense, and it becomes clear that Iowa will square off against one of the best defenses it has played this season.

"You got a new staff — they’re on the same page, they’re playing well, and they’re playing aggressively," Ferentz said. "They’re doing a great job."

Michigan is still playing plenty of veteran mainstays such as safety Jordan Kovacs — who will return against the Hawkeyes after sitting out last week because of a knee injury — and defensive lineman Mike Martin, but three freshmen have also been inserted into the starting lineup.

"They’re feeling comfortable with the defense," Mattison said in a press conference this week. "Like I tell them all the time, once you put in a defensive scheme, it becomes [the players’] defense. They’re the ones who have to run with it."

Mattison has led the turnaround for Michigan, a program that struggled to find its identity defensively under its previous coaching staff.

The Wolverines will be tested, too; the defense, which typically uses a standard 4-3 scheme, faces a quarterback on Saturday that is second in the Big Ten in passing, the conference’s leading rusher, and the league’s second-leading receiver.

But while James Vandenberg, Marcus Coker, and Marvin McNutt have done their part, the Hawkeyes will have to execute to a T on Saturday — especially after their 22-21 loss to Minnesota on Oct. 29.

"We know we need to play better. We didn’t play as well as we could [against Minnesota], and that’s what it comes down to," Vandenberg said. "We didn’t execute. There were plenty of plays out there to win the game, and we weren’t able to do it."

Iowa has primarily leaned on big run gains from Coker and deep passing routes to McNutt to put points on the scoreboard, and the Hawkeyes will need other skill players to contribute in Kinnick Stadium.

Mattison said he’s well aware of the fade route Vandenberg and McNutt enjoy, and he said his defense will pay careful attention to the 6-4, 215-pound receiver.

"I think you’ve got to make sure you’re staying tight to him and don’t look back. When a guy catches a fade a lot of times, it’s because a lot of [defensive backs] look back at the ball," he said. "We’re going to have to do a great job on him … We need to play Michigan defense."

McNutt said Iowa will need to display a sense of urgency against the Wolverines after the loss to Minnesota. If not, the Hawkeyes may be searching for even more answers as the schedule nears its close.

"The challenge is to do better offensively, continue to execute, finish drives, and not hurt ourselves," McNutt said. "It’s going to come down to who makes the fewest mistakes and has the mindset to improve.

"We need to move forward now."