But wait, isn't Oregon also standing in Arizona's way?
"We are in a position to reach just about every goal," Arizona Coach Rich Rodriguez said this week.
Oregon and Arizona, teams from opposite ends of the league spectrum, meet Friday night at Levi's Stadium in Santa Clara for the Pac-12 championship.
Oregon was heavily favored to win the North division, and did. Arizona was picked to finish fourth in the South, but didn't.
Friday's game could be a de facto national quarterfinal game.
Oregon is ranked No. 2 and Ducks quarterback
But Arizona is also a possibility for the playoffs after the Wildcats jumped to No. 7 this week in the College Football Playoff ranking.
Arizona has two losses, but a win Friday night would make the Wildcats champions of the nation's first- or second-best conference. And the 12-member playoff committee has already shown deference in evaluating the merits of Pac-12 schools.
One week, Pac-12 schools ranked 17 total positions higher in the committee ranking than they did in the USA Today coaches' poll. Six of 25 schools in this week's committee ranking hail from the Pac-12. And no other team contending team would be able to match Arizona's two wins over Oregon, which would have been ranked in the top three at the time of each loss.
The question before the committee come Sunday might be: How do you leave Arizona out?
Working against Arizona are losses to UCLA and USC and a less-than-stellar nonconference schedule.
Oregon doesn't have those issues. The Ducks have won seven consecutive games by an average of 24 points. They also have the nation's best player in Mariota, who is playing like Superman in a green cape.
Mariota has accounted for a best-in-the-nation 48 touchdowns — 36 passing, 11 rushing, one receiving.
Lost in Oregon's early coronation is that Arizona has defeated the Ducks in each of the last two seasons.
Last year's game wasn't even close; Oregon's national title dreams were deserted in a 42-16 loss in Tucson. This year's game was close, but Arizona won at Eugene, 31-24.
The Ducks used to have a
Some people are wondering now whether Oregon has an Arizona problem.
"They have beaten us twice," Oregon all-purpose back/receiver Byron Marshall said after last week's win over
Arizona poses different problems because, unlike Stanford, it is a mirror image of Oregon. If the Wildcats had not won the last two games, they might be called "Oregon Light."
Oregon Coach Mark Helfrich said the football programs are like cousins. The teams run the same read-spread offense with quarterbacks who grew up in Hawaii — Mariota and Arizona freshman Anu Solomon — at the controls.
It's too early to say whether Arizona has Oregon's number. The last two games had extenuating circumstances. Last season, Mariota was playing with partially torn knee ligaments. This season, the Ducks' offensive line was in disrepair without injured left tackle Jake Fisher.
The Ducks would argue they aren't the same team that lost to Arizona in Eugene. Oregon has sorted out its line issues and is playing at an extremely high level.
"We're different, they're different," Helfrich said. "It's a different situation."
Mariota has been unstoppable since the loss to Arizona. A photographer even caught him in what resembled a Heisman pose last week as Mariota hurdled an Oregon State player.
But Friday is Mariota's real Heisman moment. In his brilliant career, he is 0-2 against Arizona and 22-1 against all other teams.