Posted by ESPN.com's Adam Rittenberg
After going 3-9 last season, Michigan needed only two weeks to return to the national rankings.
The Wolverines come in at No. 25 in this week's AP poll after upsetting No. 18 Notre Dame on Saturday at the Big House. Michigan is back in the poll for the first time since the end of the 2007 season, when it knocked off Florida in the Capital One Bowl.
Penn State moved up two spots to No. 5, where it's tied with Mississippi. Both the Lions and Rebels are well back of the top four teams in voting.
Ohio State dropped three spots to No. 11 after its 18-15 loss to USC, which held at No. 3. Interesting to think where the Buckeyes would have ended up had they held on for the win (No. 4?).
Both Iowa and Minnesota received votes in the poll.