The Year of the Quarterback.

That’s the unofficial preseason theme in the Pac-12 as fall camps open around the conference without many battles at the sport’s most important position.

Ten starting quarterbacks return to lead their teams, including Heisman Trophy candidates and projected first-round NFL picks Marcus Mariota (Oregon) and Brett Hundley (UCLA). Only Arizona and Washington will have to break in unproven signal-callers.

The Pac-12 has eight quarterbacks on the Davey O’Brien Award watchlist for the trophy presented annually to the nation’s best quarterback.

“Never seen anything like this where you have multiple guys in our conference that you could say could be the No. 1 pick overall in the draft,” Stanford coach David Shaw said. “You have multiple guys in the conference that could be all-Americans and could lead the nation in quarterback rating or lead the nation in yards and yards per attempt or in touchdown passes.

“And that could be any of five or six guys that could do that this year.”

Oregon State’s Sean Mannion led the Pac-12 with 4,662 passing yards and 37 touchdowns in 2013. Mike Riley, who coached the San Diego Chargers between his stints in Corvallis, believes there is still plenty of room in the NFL for pocket passers.

“There is no doubt about it that Sean has an NFL future,” Riley said. “He had a chance to come out early and he was going to be drafted relatively high this year, if he wanted to. I’m glad that he decided to stay with us.”

Arizona State’s Taylor Kelly earned all-conference second team honors behind Mariota after throwing for 3,635 yards and 28 touchdowns last season. He also ran for 608 yards to lead the Sun Devils to an 8-1 conference record and a South Division title.

“It definitely motivates me,” Kelly said of not being mentioned as a Heisman Trophy candidate with some of his peers. “I’ve always been the underdog my whole high school career, my whole college career.

“I have that chip on my shoulder to be the hardest worker. I can only produce what I can do and control what I can control.”

USC’s Cody Kessler threw for 2,968 yards and 20 touchdowns in his first season as the Trojans’ starter. Now he will be the focal point of Steve Sarkisian’s more up-tempo offense.

“I’ve always admired Cody’s competitiveness,” said Sarkisian, who tried to recruit Kessler to Washington out of high school. “He’s got a big heart, he’s a tremendous leader and he’s talented. I think Cody fits our scheme very well. I expect him to have a very good season, quite honestly.”

At the bottom of the South Division, Utah’s talented dual-threat quarterback, Travis Wilson, has been cleared to play after a health scare last season. Colorado’s Sefo Liufau is poised for a breakout season after starting as a true freshman.

“It’s a quarterback-driven game,” said Utah coach Kyle Whittingham, who hasn’t been able to keep a starter healthy for an entire season since 2008 when the Utes finished 13-0 with a Sugar Bowl win against Alabama. “If you have a guy that pulls the trigger and can make plays for you at a high level, you have a chance every week. This conference is loaded with them.”

Stanford might have to lean on Kevin Hogan — who had only to complete 7 of 13 passes for 103 yards in the win against Oregon — because of the graduation of running back Tyler Gaffney and a reshuffling defense. The 6-foot-4, 228-pound senior threw for 2,630 yards and 20 touchdowns in 2013.

Washington State’s Connor Halliday enters his final season in Mike Leach’s system after throwing for 4,597 yards and 34 touchdowns to lead the Cougars to a bowl game for the first time in 10 years.

Jared Goff gives California some hope after setting the Bears’ freshman passing record with 3,508 yards during a painful 1-11 season.

“I don’t think there is a conference that’s close in terms of quality of quarterbacks. And that’s not to say they’re all going to be great NFL players, but they’re great college football players,” said UCLA coach Jim Mora, the former coach of the Atlanta Falcons and Seattle Seahawks. “Every week you get ready to play a Pac-12 quarterback and there is a trait that they have that is unique. That’s difficult to defend.

“I have great respect for the quarterbacks in this conference.”

Mariota and Hundley decided to return for their redshirt junior seasons instead of entering the 2013 NFL draft. They are among the primary challengers to dethrone reigning Heisman Trophy winner Jameis Winston of Florida State.

“I can’t wait for some of these guys to get out of our conference, which I thought a couple would happen last year and they disappointed me and came back,” Shaw said.

“But I think it’s going to make for exciting football.”