EUGENE, Ore. >> Oregon opened fall camp on Monday as the early favorite in the Pac-12. There’s good reason: Quarterback Marcus Mariota is back.

Mariota, who was an all-star at St. Louis School in Honolulu, averaged nearly 282 yards passing per game and threw for 31 touchdowns with only four interceptions last season for Oregon. He also rushed for 715 yards and nine scores. His 4,380 yards of total offense set a school record.

There was speculation last season that he’d jump to opportunities in the NFL, but Mariota announced early on that he was sticking with the Ducks.

On Monday, Mariota said his decision didn’t have all that much to do with “unfinished business” after Oregon lost two games last season to fall out of national championship contention.

“For me I wanted to come back and get my degree, come back and enjoy another year with the guys and experience college for another year,” he said.

Experiencing college for another year for Mariota means taking classes in — seriously — yoga and golf. The junior quarterback already has his degree in general science, wrapping up his studies in three years.

In large part because of Mariota’s return, Oregon has been picked in the annual poll of reporters who cover the conference to finish this season atop the Pac-12 North and claim the league’s championship.

Oregon was ranked No. 4 in the preseason Amway coaches poll. The AP Top 25 will be released Aug. 17.

Mariota was a Heisman contender last season before struggling with a left knee injury. The Ducks had climbed to No. 2 in the AP rankings and were seemingly on course for a national championship bid. Then came Stanford.

It turns out Mariota had partially torn the medial collateral ligament in his left knee against UCLA the week before and the Cardinal beat the Ducks 26-20.

The Ducks rebounded to beat Utah, but then fell 42-16 to the fired-up Arizona Wildcats in Tucson. The loss dropped Oregon to No. 12 and skewered the Ducks’ chances of a national championship bid.

The Cardinal went on to claim the Pac-12 North and beat Arizona State in the league championship to earn a spot in the Rose Bowl.

After wrapping up the regular season with a 36-35 victory over Oregon State in the Civil War, the Ducks beat Texas 30-7 in the Alamo Bowl to finish 11-2 and ranked No. 10.

“Injuries happen,” Mariota said on Monday. “We’re not going to let my knee be an excuse for what happened last year. All we can do is try to learn from it and try to get better.”

Going into fall camp, Jeff Lockie appears most likely to earn the job as Mariota’s backup. Jake Rodrigues and Damion Hobbs transferred, so the team has sophomores Lokie, Taylor Alie and promising incoming freshman Morgan Mahalak competing for second-team reps.

Lockie came off the bench in nine games last season, completing eight of 13 passes with an interception and no touchdowns. Coach Mark Helfrich said he believes that after a good spring, Lockie is up for the challenge.

“He needs to trust himself a little bit more, believe in himself a little bit more,” Helfrich said.

Like Mariota, center Hroniss Grasu and cornerback Ifo Ekpre-Olomu also decided to return to the Ducks for another season. Running back De’Anthony Thomas and cornerback Terrance Mitchell decided to leave the team early for the NFL draft.

Helfrich is embarking on his second year as head coach after his promotion from offensive coordinator when Chip Kelly made the leap to the Philadelphia Eagles.

While many of the players said last season’s losses have them eager to get back on the field, Helfrich said last year doesn’t change what the Ducks are doing this year.

“As long as our guys believe in our process and trust our process, everything will fall into place,” he said.