USC’s Justin Davis is making a case to start at tailback

It is no longer rare for freshman tailbacks to start season openers for USC.

C.J. Gable became the first true freshman to achieve the feat in 2006 and D.J. Morgan did it as a redshirt freshman in 2011.

The Trojans’ Aug. 29 opener at Hawaii is still months away, but Justin Davis might earn the opportunity to join that select group if he performs during training camp as he has in spring practice.

Davis, who graduated from Stockton Lincoln High in December, rushed for 116 yards and a touchdown in 17 carries Saturday during a situational scrimmage at the Coliseum.

Knee injuries suffered this spring by Silas Redd and Morgan opened the door for Davis.

If Redd recovers from surgery as anticipated, it’s probable that the senior would be at the top of the depth chart in the fall.

But the 6-foot-1, 215-pound Davis could challenge upperclassmen for playing time and, perhaps, a starting role.

“We’re going to play the best guy,” said Coach Lane Kiffin.

Redd, Morgan, Davis and third-year sophomore Javorius Allen will be joined this summer by freshman Ty Isaac.

Redd transferred to USC from Penn State on the eve of training camp last year and finished the season with a team-best 905 yards rushing and 10 touchdowns. He underwent surgery a few weeks ago and is expected to return for summer workouts.

Morgan has been sidelined for about a week because of knee soreness but might return Tuesday for the final week of spring workouts, Kiffin said.

The 6-1, 210-pound Allen quietly continues to show great improvement. The Florida native rushed for 42 yards in 10 carries Saturday and made a highlight-reel play when he moved the pile more than 10 yards before breaking free and running over an official en route to a 17-yard gain.

But Davis has been the talk of spring workouts, bursting through the line for long gains and also running tough in short-yardage situations.

“This wasn’t the fastest tailback in the country,” Kiffin said. “But we saw [in high school] he was a great runner.”

Lee factor

All-American receiver Marqise Lee, who suffered a knee injury March 9, participated in a scrimmage for the first time this spring.

Not surprisingly, the offense picked up.

“I just try to be a motivator,” said Lee, who caught 10 passes for 191 yards and two touchdowns.

Lee’s presence created better opportunities for quarterbacks Max Wittek, Cody Kessler and Max Browne, sophomore receiver Nelson Agholor and tight end Randall Telfer.

“I saw first-hand how quick and how good he really is,” Browne, a freshman, said of Lee. “He’s a quarterback’s best friend.”

All three quarterbacks performed efficiently, but Kiffin said “we’re not any closer” to naming one of them the projected starter.

Quick hits

Wittek completed 14 of 17 passes for 200 yards and two touchdowns. Kessler was 12 for 21 for 120 yards and a touchdown, Browne six for seven for 85 yards and two touchdowns…. The quarterbacks, Kiffin and Lee all praised the play of the offensive line…. Agholor caught six passes for 91 yards and two touchdowns…. Kiffin said coaches were “leaning toward” having two-year starting linebacker Dion Bailey play safety in the fall. Kiffin reiterated that “we’ve got a lot of issues” at cornerback and that safety Josh Shaw could be moved back to that spot, where he started the final seven games last season.

gary.klein@latimes.com

Twitter: @latimesklein