USC struggling to put up points

USC features a third-year quarterback who passed for 26 touchdowns last season, a top NFL prospect at left tackle, one of college football’s most dynamic receivers and a stable of tailbacks including several ranked among the nation’s top recruits of the last five years.

Yet the Trojans’ offense has scored only one touchdown in the second half this season.

“We’ve had glimpses of what we’re capable of — mostly in the first half,” quarterback Matt Barkley said Wednesday.

After victories by 19-17 over Minnesota and 23-14 over Utah, the Trojans are averaging 21 points a game, ranking 91st nationally among 120 major-college teams. But that average includes cornerback Torin Harris’ last-second touchdown after a blocked field-goal attempt against Utah.

Without it, USC would be averaging 18 points a game. That would rank the Trojans’ 100th.

“It’s very frustrating,” said Coach Lane Kiffin, who once called the shots for a 2005 USC offense that averaged 49 points a game.

USC sabotaged itself against Utah with an interception, two fumbles and penalties that wiped out big plays.

The Trojans are more than a two-touchdown favorite over Syracuse on Saturday, but they could be in for another close game if the offense continues to sputter after halftime.

“It’s just stupid, it’s frustrating, because I know we’re capable of so much more,” Barkley said. “But we just shoot ourselves in the foot.

“It’s little things, so I think I can do a better job of telling my teammates, especially the 11 that are in, just keeping them focused and keeping them in tune with what we need to do.”

Kiffin and Barkley attribute many of the offensive missteps to youth and a lack of game experience.

Barkley’s interception and fumbles by redshirt freshman tailback D.J. Morgan and redshirt freshman tight end Xavier Grimble all occurred within Utah’s 20-yard line. A long catch-and-run play by freshman receiver Marqise Lee was nullified because Lee lined up out of formation.

“A lot of those drives have come down to freshman mistakes,” Kiffin said. “Hopefully, we’re getting through those.”

Crenshaw connection

Former Crenshaw High lineman Marcus Martin continued to work with the first-string offense at left guard and appears on track to start against Syracuse.

If Martin starts, he would be the first USC freshman to do so at guard since Jeff Byers, who started four times late in the 2004 season.

Kristofer O’Dowd started three games at center as a freshman in 2007.

Quick hits

Kiffin said that junior safety Drew McAllister would play as a backup to T.J. McDonald against Syracuse and that freshman linebackers Lamar Dawson and Tre Madden and cornerback Anthony Brown also would play more. … Quarterback Jesse Scroggins, who had the cast removed from his surgically repaired right hand last week, said that there was still no timetable for his return, but that he was making progress in rehabilitation.

gary.klein@latimes.com

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