Freshman could get start at center

Call it a snap decision.

A day after USC coaches said junior left guard Jeff Byers would move to center in place of injured Matt Spanos, freshman Kristofer O’Dowd took nearly all of the first-team snaps on Thursday in the Trojans’ final full practice before Saturday’s opener against Idaho.

The 6-foot-5, 300-pound O’Dowd is on track to become the first true freshman to start a game at center for the Trojans.

“The more I look at it, why should we move two guys because one guy’s not in there?” Coach Pete Carroll said.

O’Dowd declined to comment, citing instructions from the coaching staff.

Byers had practiced with the first unit on Wednesday and was looking forward to his first start at center, the position he played in high school when he was the Gatorade national player of the year.

But Byers acknowledged that his lack of snaps during training camp made for less-than-smooth exchanges with quarterback John David Booty.

“I kind of regret not getting more snaps and I’m sure [Booty] does and the coaching staff as well,” Byers said.

Booty said he was comfortable with O’Dowd, who has been working as Spanos’ backup.

“He’s got to step up but from what I’ve seen and the way we’re handling snaps, everything seems to be running smooth,” Booty said.

According to USC officials, the last true freshman to start an opener on the offensive line was guard Travis Claridge against Penn State in 1996.

Guard Brad Budde was the only other true freshman offensive lineman to start a post-World War II opener. Budde played against Missouri in 1976.

Freshman tailback Broderick Green had been running smoothly and powerfully until Thursday when he finally told trainers about pain in his left foot.

Green had X-rays and did not practice. Carroll said the preliminary diagnosis was a stress fracture and that Green would not play against Idaho.

Green said he was injured during the Trojans’ second training camp scrimmage at the Coliseum.

“It’s hurt for probably about a week or week and a half,” Green said. “But it’s been on and off. It’s not super bad pain. . . . I still think I’ll be able to play Saturday.”

USC, which opened training camp with 10 tailbacks, is down to five relatively healthy players at the position: sophomore C.J. Gable, who is scheduled to start a second consecutive opener; sophomores Stafon Johnson and Allen Bradford; freshman Joe McKnight and senior Desmond Reed.

Sophomore cornerback Vincent Joseph will return kickoffs against Idaho.

“Give him a crack and he’s going to be able to bust it like we’ve seen in our scrimmages,” Carroll said.

Carroll said the move also was made to alleviate some of the burden on Gable, who averaged 27 yards a return last season but has been nursing an abdominal strain.

Reed will return punts, but Carroll said freshman Ronald Johnson also would get some chances.

Junior cornerback Josh Pinkard again sat out the final half of practice because of a sore left knee. Pinkard had season-ending surgery on his right knee after the 2006 opener at Arkansas. . . . Freshman Michael Reardon was switched from the defensive line to the offensive line. . . . Booty said he has been counseling freshmen about remaining focused during the opener and told them, “Watch the older guys who have been in that situation. . . . Don’t get caught up in the crowd or there being 92,000 people.”

gary.klein@latimes.com