USC needs to figure out its offensive line before thinking of a championship

Few teams in the history of football have won a national title with a mediocre offensive line. So before USC answers questions about whether it can compete for a championship this season, the Trojans will have to address a more pressing concern.

Will the line provide enough space for quarterback Sam Darnold and running back Ronald Jones II to operate?

USC will begin to find an answer on Saturday, when it opens training camp.

The Trojans lost three significant starters from last season’s offensive line: tackles Chad Wheeler and Zach Banner and guard Damien Mama.

Removing just one of those pieces caused trouble in the past.

Wheeler missed USC’s first two games with injury, and production dipped significantly. The Trojans ranked sixth in the nation in sacks allowed per game last season, at 0.9. In the first two games, they allowed an average of 2.5. They ranked seventh in tackles for loss allowed, at 4.4; they allowed twice that, nine per game, without Wheeler.

“Our biggest challenge will be able to fill those two tackle roles,” coach Clay Helton said on Thursday during the Pac-12 media days.

Chuma Edoga started USC’s first two games last season in Wheeler’s absence (Edoga was ejected after one drive in the second game), and the coaching staff expects him to win the right tackle job in training camp.

Edoga possesses the size and athletic ability to excel and warrant NFL attention, but Neil Callaway, USC’s offensive line coach, said in the spring that he needed to see more consistency.

Toa Lobendahn and Chris Brown are the favorites to win the other open roles. Both have the ability to play multiple positions. Brown transitioned from guard to tackle in the spring to give USC flexibility. Lobendahn started at center last season before an injury, but Helton may prefer to keep his replacement, Nico Falah, at the position after Falah’s impressive finish.

But Lobendahn has suffered two major injuries to his right knee, making depth essential.

USC has recruited well enough to have options. But offensive line chemistry can be fickle and take time to build. Darnold said he has seen cause for optimism in the spring and summer.

“The o-line’s doing great so far,” Darnold said. “We have a bunch of guys that can play a lot of positions on the offensive line. We have five or six guys that have legit game experience. So that’s going to be interesting to see how it all plays out.”

With the return of Falah and guard Viane Talamaivao, Helton said he believed that “the interior core is still there.”

“I think of Nico Falah, I think of Viane Talamaivao, I think of Toa Lobendahn, those guys have played a lot of ball over the last three years,” Helton said. “And then I think of guys like Chris Brown and Chuma Edoga, even though they haven’t been starters, they’ve played a lot of ball too.”

Helton said his biggest concern entering camp was not the offensive line, but “the chemistry between Sam and our new receivers. I think they’re beyond talented, the kids that we redshirted, but they haven’t been in real live games yet.”

The roster holds no simple fill-ins for big-play threats like JuJu Smith-Schuster and Adoree’ Jackson, who both left early for the NFL draft.

Asked how he’d replace Jackson, Helton said, “I don’t know if you can.”

Instead, USC will turn to a rotating cast of young receivers, including Michael Pittman, Tyler Vaughns and Velus Jones, or freshmen such as Joseph Lewis IV.

“I know we have guys that have that big-gain potential,” Darnold said. “It’s just whether or not they hide from the light or if they shine brighter.”

zach.helfand@latimes.com

Follow Zach Helfand on Twitter @zhelfand