USC defense dominates final preseason scrimmage, without making a single tackle

USC Coach Lane Kiffin hoped to have some answers Saturday after the Trojans scrimmaged for the final time before their Sept. 2 opener at Hawaii.

But questions abounded.

For example: What’s going on with the offense?

On a day when USC did not tackle to avoid injuries, Matt Barkley had a pass intercepted and returned for a touchdown. Mitch Mustain had two passes intercepted, one in his debut against the first-team defense. The offense also fumbled twice but recovered the ball.

“Ugly,” said Mustain, who also passed for two touchdowns.

Kiffin, who doubles as the Trojans’ play-caller, praised the defense but was most happy that no player emerged injured.

With less than two weeks before the opener, Kiffin is still in search of a starting tailback, a No. 2 receiver and healthy guards for the offensive line.

Senior tailback Allen Bradford, who entered camp No. 1 on the depth chart, did not participate in the 111-play scrimmage because of a left knee bruise suffered Friday. Bradford said he hoped to return Monday.

He might push it based on Kiffin’s assessment of the position group.

“Nobody’s the starting tailback,” he said.

Sophomore receivers Brice Butler and De’Von Flournoy both made impressive one-handed touchdown catches in their bids to start opposite senior Ronald Johnson. Kiffin noted both plays, but wants more consistency from a group that also includes freshmen Robert Woods and Markeith Ambles.

“Too many mistakes,” Kiffin said. “We play too slow.”

Meanwhile, the defense looked fast and dominating behind a front seven that included junior Chris Galippo working as the first-unit middle linebacker.

Cornerbacks Shareece Wright and Torin Harris, freshman safety Dion Bailey and defensive lineman Hebron Fangupo intercepted passes. Wright, who returned his 35 yards for a touchdown, said the Trojans defense was coming together but was eager to play a real opponent.

So, no doubt, is the offense.

“We’re all getting frustrated,” Wright said. “We’ve been beating up each other for a month. . . . We can’t wait to let that out on someone else.”

Poll position

USC, ineligible for the Bowl Championship Series title and inclusion in the coaches’ poll, is ranked 14th the Associated Press preseason poll.

“I have zero concern of where we get ranked in a poll,” Kiffin said. “We haven’t won a game yet, haven’t made a first down. We’ve done nothing so that’s completely meaningless.”

Asked whether he was happy for the Trojans to at least be recognized, Kiffin said, “I guess. I don’t really understand it.

“You can be ranked in one poll but you can’t in another, so I’m not probably a very good person to ask about that. [It] doesn’t make very much sense to me.”

New arrival

Kiffin announced after the scrimmage that Thearon Collier, a receiver and kick returner at Miami the last two seasons, would enroll at USC and be eligible in 2011. The Palm Beach Post reported this month that Collier was dismissed from Miami for violating team rules.

Quick hits

Barkley completed 13 of 29 passes, two for touchdowns. Mustain was 14 for 27 and walk-on John Manoogian was three for five with an interception. . . . Joe Houston kicked a 33-yard field goal and converted all five of his extra-point attempts. . . . Bailey, who had been sidelined for most of camp because of a concussion, made 10 tackles. . . . The Trojans do not practice Sunday. They resume workouts Monday.

gary.klein@latimes.com