Oregon can make sure the Pac-10 race stays very simple with a win at Arizona on Saturday.
But if the Wildcats can bounce back from a difficult defeat with a victory over the 11th-ranked Ducks, things will get very complicated in a conference that has often lacked surprises in recent seasons.
Southern California has been to the Rose Bowl five times since any other Pac-10 school has gone, but that streak is almost certain to end this season. Oregon can make it official Saturday by winning for the ninth time in 10 games.
The Ducks (8-2, 6-1) are the league's only remaining team with one loss in conference play, and they would secure a spot in Pasadena by beating the Wildcats and rival Oregon State.
But Arizona (6-3, 4-2) is one of three clubs -- along with Stanford and Oregon State -- with two Pac-10 defeats, and the Wildcats could also secure their first trip to the Rose Bowl with wins in their final three games. They visit Arizona State and USC after Saturday's contest.
"We know we've got to win to stay in the big picture," Arizona coach Mike Stoops said. "There's a lot of football to be played, but pretty much it'll be over if we don't win on Saturday."
That will be a tough task against the Ducks, who are tied for the nation's sixth-best rushing offense even though star sophomore LeGarrette Blount has been suspended for nearly the entire season after throwing a punch following a 19-8 loss at Boise State in the opener.
Blount was reinstated before last Saturday's 44-21 win over Arizona State, but he did not play as Oregon continued to rely on freshman LaMichael James, who totaled 150 yards and three touchdowns on 22 carries.
James ranks 10th nationally with an Oregon freshman-record 1,193 rushing yards, including more than 100 in five straight games.
"LaMichael had a great game (against Arizona State) and showed again why he's one of the best in the nation. We're going to ride him as long as we can," Oregon coach Chip Kelly said.
"He has confidence and speed. He is a dangerous guy," the coach added. "It is tough to knock him off of his feet and he understands the game offensively."
The Ducks, seeking their first Rose Bowl bid since 1995, also have a major threat in junior quarterback Jeremiah Masoli, who has run for nine touchdowns and thrown for 11 while leading an offense that averages 37.1 points -- ninth-best nationally.
"We just have to stick to the script and keep doing what we've been doing," Masoli said.
Arizona figures to provide some resistance with the Pac-10's third-best rush defense, but the Wildcats tumbled from the Top 25 after they were gouged for a season-worst 176 yards on the ground at California last Saturday.
The Golden Bears were missing injured star running back Jahvid Best, but backup Shane Vereen totaled 159 yards on 30 carries in Cal's 24-16 victory.
"It put us in a pretty desperate mode right now," Stoops said.
The Wildcats also likely need to improve their offense if they hope to keep up with the Ducks. Arizona averaged 37.6 points in its first five Pac-10 games before struggling against Cal, totaling season lows in points and rushing yards (73) as starting running back Nic Grigsby was sidelined with a shoulder problem.
Quarterback Nick Foles attempted 41 passes but threw for just 201 yards, his third straight game under 250 after he averaged nearly 400 in meetings with Washington and Stanford in October.
It's possible Grigsby could return Saturday and the Wildcats also could benefit from playing at home, where they're 5-0. Oregon lost 34-24 in Tucson on Nov. 15, 2007, but Masoli accounted for 387 yards and five touchdowns in the Ducks' 55-45 home win last year.
"If we want to stay in this thing, we've got to win, or our visions of a championship are over," Stoops said. "And you'd better compete and understand what it's going to take to win a game like this. I look for our kids to take on that challenge and respond in a positive way."
AccuScore has powered more than 10,000 simulations for every College Football game on ESPN.com, calculating how each team's performance changes in response to game conditions and opponent's abilities. Each game is simulated and the game is replayed a minimum of 10,000 times to generate forecasted winning percentages.
Oregon and Arizona both control their respective destinies in getting to the Rose Bowl, but they'll have to get past each other to reach Pasadena. The Ducks come into the game with the nation's sixth-best ground attack, and the Wildcats boast the 20th-ranked rushing defense.