Crist's regular-season stay lasted about as long as Notre Dame occupied a spot in the Top 25. The Irish were knocked out of the poll Tuesday following their stunning loss to USF on a wild day interrupted by dangerous weather.

Just two weeks ago, Crist was announced as the starter after beating out Rees in training camp. Kelly said at the time he expected the senior to keep the job for the rest of the season.

But Crist's uneven performance Saturday and Rees' strong relief job in the second half prompted the change.

"A very difficult situation that I felt needed to be addressed," Kelly said.

"I want to win right now. I believe Tommy gives us the best chance to win against Michigan. There are so many things you do within your program that you build for the future. Recruiting is always about building for the future. But your roster has to be evaluated about how to win right now. Especially at Notre Dame."

Kelly called Saturday's loss "probably one of the most frustrating experiences that I've ever had as a head football coach. I mean, extremely frustrating. Everybody was frustrated."

And Kelly, who gave Crist an earful on the sideline as the Irish fell behind 16-0 at the half, erupted in the second half after a Rees pass hit receiver TJ Jones and was intercepted as the Irish were in position to score. Notre Dame had five turnovers in the game, three interceptions.

TV cameras showed Kelly screaming at Jones and the coach's outrage prompted criticism across chat boards, websites and publications.

Asked about his demeanor Tuesday, Kelly first answered with a question to a reporter: "Did I hit somebody? Did I strike somebody? Is that what you're referring to? I'm asking specifically what you're referring to."

Told that there were numerous articles about his sideline outburst, Kelly acknowledged that with the cameras on him -- Notre Dame's games are televised by NBC -- he has to be more careful.

"Yeah, I think I was extremely frustrated with the game. You know, what I have to recognize is that I'm on TV all the time," he said. "You know, do a better job of understanding when that camera is on me. Seems like it's on more than I'm used to. So I'll have to do a better job of controlling my emotions."

It will now be up to Rees to lead the team against the Wolverines (1-0).

Rees, who won four games as the starter to close last season after Crist suffered his second season-ending knee injury in as many years, looked much more comfortable and got rid of the ball quicker. He completed 24 of 34 passes for 296 yards with a pair of TD passes to Michael Floyd, who caught 10 of his 12 passes Saturday from Rees.

Rees was also good last season against Tulsa after Crist got hurt. He put up big numbers in that game -- 33 of 54 for 334 yards with four TD passes -- but also threw a last-second interception in a tough loss.

Going to Michigan's massive 10,000-plus-seat stadium will be another stop at a marquee venue for Rees. The sophomore started games last season at Notre Dame Stadium, Yankee Stadium and the Los Angeles Memorial Coliseum. He also started the Sun Bowl victory over Miami.

If Rees is productive, it's his job to keep.

"Nobody wants to go in and change their quarterbacks each and every week. That's just not the way you play this game," Kelly said.

"So we don't come to this decision thinking, 'Well, he'll give us one game and then we'll go back to Dayne.' That's obviously not why we made this decision. We believe that Tommy is capable of leading this football team, just as I believed strongly that Dayne is capable."

Crist did some good things in the first half when the Irish fell behind against USF 16-0, Kelly said. A long opening drive was stymied by Jonas Gray's fumble near the goal line, and a TD run by Cierre Wood was called back by a holding penalty just before Crist threw an interception in the end zone.

But Crist didn't make his decisions quick enough Saturday and there were too many mistakes, certainly not all of his making.

"You know, it wasn't all Dayne Crist," Kelly said. "Unfortunately it falls on the quarterback as the leader to be productive. That's why we went with the decision. ... I'm not here to cover Dayne's butt, OK? That's not by job. ... The difference between being good and great sometimes is being decisive. You know, not whether you can process and understand, but decisiveness."

Rees, an early enrollee last year, hails from a football family. His dad has an extensive background in coaching and personnel in both the NFL and college ranks, and his brother was a punter and holder at UCLA.

He actually made his college debut last season against Michigan when Crist was shaken up in the first half. Rees threw two passes, one of them intercepted, and was obviously not ready for the stage at that time and was quickly yanked in favor of Nate Montana.

Now he's relaxed and able to keep cool when he's in the game or on the sideline.

"Obviously it's been a pretty up and down couple of weeks," Rees said. "When I found out Dayne would be the guy, obviously I was disappointed, but at the same time excited for him. He deserved it. ... Now I'm getting my chance, he's been the same way to me. It's such a good relationship."