A home loss to USC dropped Oregon down to 10th in latest BCS poll, out of the equation for a shot at playing for the BCS title.
The Ducks now have a must-win against Oregon State in their Civil War matchup to play in the inaugural Pac 10 title game and have a shot at the Rose Bowl. Oregon was favored by 28 points Monday morning.
A second LSU-Alabama game could determine the BCS championship.
A weekend filled with upsets left the Southeastern Conference rivals in the top two spots in the BCS standings released Sunday.
And Arkansas is third, further increasing the possibility of an all-SEC BCS championship game Jan. 9 in New Orleans that would be a rematch of a regular-season game.
It's the first time in the 14-year history of the BCS that the same conference had to top three teams in the standings. If the Tigers can beat Arkansas on Saturday, then Georgia in the SEC title game Dec. 3, and the Crimson Tide beats Auburn on Saturday, it's almost a lock that LSU-Alabama will play again, this time at the Superdome.
LSU beat Alabama 9-6 in overtime Nov. 6 in Tuscaloosa. Oklahoma State, which suffered the most surprising loss of the weekend, fell to fourth place. The Cowboys were unbeaten and second in the BCS standings, but were upset 37-31 in double overtime at Iowa State on Friday night.
"You just never know what to expect any more with what happens every Saturday," Oklahoma State coach Mike Gundy said.
Still, Oklahoma State is not out of it. The Cowboys just need some help from Auburn and LSU or from voters in the Harris and coaches' polls who don't have an appetite for a rematch in the BCS championship game.
"Oklahoma State is still the most viable team if we get to two weeks from now and there is still a pull to not have a rematch of some sort," said Jerry Palm, who analyzes the BCS standings for CBSSports.com.
BCS pairings are announced Dec. 4.
Also undercutting the Cowboys chances is the loss by Oklahoma to Baylor on Saturday. Oklahoma State plays Oklahoma on Dec. 3. "Now if Oklahoma state wins that game, (the Cowboys) just don't get the push they might have gotten otherwise," Palm said.
Oklahoma slipped fifth to ninth in the standings. Oregon, which lost 38-35 to SouthernCalifornia, fell from fourth to 10th in the standings.
That left the SEC in control.
If LSU gets past Arkansas, it would seem a case could be made that the Tigers could lose to Georgia in the SEC title game and still play for the national championship.
LSU would be a one-loss team like all the rest and have maybe the best resume of the bunch with victories against Oregon and West Virginia out of conference.
Palm isn't sold on that scenario.
"That could be the scenario that gets Oklahoma State in," Palm said. "Hard to imagine (the voters would) put two teams that didn't win their league in the top two."
Virginia Tech is fifth in the BCS standings with a game against Virginia on Saturday that will determine which team plays Clemson for the Atlantic Coast Conference title.
Stanford is sixth with a game against Notre Dame left. The Cardinal could reach the Pac-12 title game if Oregon were to lose to Oregon State on Saturday.
The Hokies and Cardinal have national title hopes, but would need lots of help in the form of losses by the teams ahead of them to get there.
Boise State is seventh, but the Broncos will be shut out of the BCS this season because they can't win their conference after losing to Mountain West Conference rival TCU.
Undefeated Houston is eighth and can lock up the BCS buster bid by winning conference USA. The Cougars play Tulsa this week and would host the C-USA title game, most likely against Southern Mississippi, if they beat the Golden Hurricane.