USC and Oregon could also meet in the Pac-12 title game.
Trojans-Ducks might be only the second-biggest game of the day on Nov. 3.
That will also be the day of Round III of Alabama-LSU, after the Tide and Tigers played twice last season, the second time in the BCS title game.
Alabama won the rematch 21-0 to take its second national title in the last three seasons under coach Nick Saban. The Tide are rebuilding on defense, but return quarterback A.J. McCarron and one of the best offensive lines in the country.
LSU has a new quarterback, Zach Mettenberger, who the Tigers hope will give the passing game more punch, and much of last year's fearsome defense is back — except Mathieu.
The defensive back nicknamed Honey Badger became a surprising Heisman contender with a slew of game-changing plays last season. He scored four touchdowns, two on punt returns and two on fumble returns.
His departure was met with mixed reaction by voters, but in a tight race for No. 1 it made a difference.
"Tyrann Mathieu's a terrific player, but I don't think the overall effect will change LSU's results," said John Silver from the Journal Inquirer of Connecticut, who did not change his ballot after the Mathieu news. "I don't think a corner can make that big of a difference. It hurts them, but at the margins."
Seth Emerson of The Macon (Georgia) Telegraph dropped LSU from No. 1 to No. 3, behind Alabama and USC.
"On the one hand, he wasn't exactly known as a lock-down cornerback and LSU has plenty of other talent. On the other hand, I was in the Georgia Dome last year when Mathieu single-handedly turned the tide of the SEC championship," Emerson wrote on his blog. "He's a dynamic player. There's a reason he was fifth in the Heisman voting.
"That's why I moved LSU to third, but not any further down."
The rest of the Top 25 was heavy on Big 12 and Big Ten teams.
Big 12 newcomer West Virginia was 11th, followed by Big Ten rivals Wisconsin and Michigan State.
The Big 12 also placed Texas (No. 15), Oklahoma State (No. 19), TCU (No. 20) and Kansas State (No. 22) in the rankings to give the league six teams overall, matching the SEC for the most.
No. 23 Florida is the sixth SEC squad.
The Big Ten added Nebraska (No. 17) and Ohio State (No. 18) for a total of five teams. The Buckeyes, in their first season under coach Urban Meyer, are banned for the postseason this season because of NCAA sanctions.
Defending Atlantic Coast Conference champion Clemson (No. 14) and Virginia Tech (No. 16) give the ACC three teams in the Top 25.
No. 21 Stanford is the third Pac-12 team in the poll.
No. 24 Boise State is ranked in the preseason for the fourth straight year and No. 25 Louisville is the only Big East school in the rankings.
Follow Ralph D. Russo at www.Twitter.com/ralphDrussoAP
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