One of Saturday's scarier plays also served as a stepping stone for one of Michigan's future stars.

Freshman Justin Boren saw substantial time on the offensive line in the second half, filling in for an injured teammate four years his elder.

With Michigan holding onto a three-point lead in the third quarter, quarterback Chad Henne was sacked and fumbled at Michigan's 30-yard line. Right tackle Rueben Riley, whose man beat him and caused the fumble, streaked across the field to recover the ball for a 12-yard loss. He then limped to the sideline, where he stayed for the rest of the game.

Riley first tweaked his leg during the final seconds of the first half. He fell to the ground and didn't immediately get up, but eventually limped off after getting help from a trainer.

After watching the first five plays of the second half from the sideline, Riley tried giving it another chance. But his first play back was when his man sacked Henne and forced the fumble, and Riley knew it was time to hang it up for the afternoon.

"I couldn't go anymore, so I had to yank myself," Riley said.

Starting right guard Alex Mitchell shifted to Riley's right tackle spot and true freshman Justin Boren stepped in at right guard.

Some were critical of Michigan coach Lloyd Carr for burning Boren's redshirt during the late stages of the Michigan State game. But Carr defended his decision, citing that the team was just an injury away from needing someone young to step up.

That time came on Saturday, and the true freshman did everything he was called upon to do in his first extensive playing time of the season.

The Wolverines didn't hesitate to test Boren's abilities, either. They ran right behind him on his first play in the game: a run to the right where junior Mike Hart picked up five yards thanks in part to a pancake block from Boren.

"It's really good to see the young guys get in there," Mitchell said. "I'm really happy for him, and he did a great job. He's still got some things to work on, but for stepping in at a game like Iowa, he did a great job."

Boren also got Hart's endorsement, which isn't surprising considering the junior running back gained the majority of his 126 yards while Boren was on the line.

"Boren did a great job today," Hart said. "I've always had confidence in him because he's a great player. He's strong and smart, so he did a great job out there (Saturday)."

Trouble ahead?: Internet reports leading up to Saturday's game indicated that wide receiver Adrian Arrington might be suspended against Iowa for an off-field issue.

The Detroit Free Press reported that a police report exists regarding Arrington and an assault, but that charges were not filed.

Carr chose not to suspend the sophomore for the game, and just briefly talked about the situation during his post-game press conference.

"I'm going to be very brief," Carr said. "There's an issue, and I'm not going to discuss it except to say I take any allegation of this type very seriously. But I do not think the allegation is supported by the facts."

Arrington was not made available for comment following Saturday's game. He finished the contest with eight catches for 79 yards.

Bo knows football: Former Michigan coach Bo Schembechler was hospitalized Friday after experiencing dizziness while taping a radio show on Friday.

But Schembechler, known for his legendary stubbornness, lived up to his reputation when Carr visited on Friday night.

"His doctor came in, and Bo said, 'I want to go home tomorrow morning because then I'll be able to watch the game on my big-screen TV,' " Carr said. "He was complaining before that, 'They're not going to let me watch the game tomorrow,' because his heart was racing.

"I said, 'Well Bo, there are a few things more important than this football game tomorrow. Staying alive is one of them.' "

Schembechler also made sure to have an announcement made in the press box during Saturday's game that he was indeed watching the game. He is staying at the university's cardiovascular unit, and may stay for a couple more days.

I see red: Touchdown continues to be a four-letter word for the Wolverine defense.

Iowa made it to Michigan's red zone three separate times on Saturday, but each time, the nation's top rushing defense kept the Hawkeyes out of the end zone.

"When they're in the red zone, our coaches came up and talked to us and said 'You can't let them in, you can't let them in,' " nickelback Brandon Harrison said. "So we just all looked at each other and made sure we wouldn't let them in."

Going into the game, Iowa prided itself on its reputation as a tough and physical team. But this distinction didn't help the Hawkeyes in the trenches when they needed it the most on Saturday.

"They said they were the bully of the Big Ten," defensive tackle Terrance Taylor said.