Turnovers and penalties continue to haunt USC amid winning streak

On Friday, the day after USC defeated California, 45-24, Coach Clay Helton attended a lunch next to the Rose Bowl, held by the Pasadena Quarterbacks Club, and fielded a series of question from fans.

One man held his hand aloft and stood when Helton called on him. With some exasperation, he groaned, simply, “Penalties!”

The room laughed. Helton nodded.

The Trojans own a four-game winning streak and are within striking distance of the Pac-12 South division lead. Yet they have been unable to shake two distressing habits: penalties and turnovers.

Against California, USC turned the ball over three times and committed 13 penalties for 125 yards, a season high by a considerable margin.

“It’s a little bit of everything, to be honest with you there,” Helton said of the penalties on a teleconference with reporters on Friday evening.

He wasn’t exaggerating much. USC had three holding penalties, two personal fouls (on consecutive plays), two unsportsmanlike-conduct penalties, two false starts, one offside, a pass interference, one penalty for an ineligible man downfield and one for an illegal formation.

A flag for 12-men on the field would’ve been USC’s 14th penalty, but it was declined.

It was an unusually large number of penalties but not entirely out of character. USC ranks 96th nationally in penalty yardage per game, with 64.

Helton said the team has practiced more often with the first-team offense playing against the first-team defense. In part, he said, it was meant to prepare the starters for the speed of an actual game to help cut down on penalties.

One reason for Thursday’s deluge of flags could’ve been the prime time game, he said.

“The biggest thing for me is when we get in that situation of being in a really excited atmosphere on national television, just keeping it the same,” Helton said.

The three turnovers could all be credited to quarterback Sam Darnold, who has transformed USC’s offense but has sometimes struggled to protect the ball. On Thursday, he fumbled while being hit from the blindside and again on a mishandled play-action fake.

He also had one pass intercepted.

“Just a dumb play,” Darnold said of the interception.

Darnold said that he has been more mindful of keeping two hands on the ball at all times, but both of Thursday’s fumbles came during his throwing motion.

“That stuff’s going to happen,” he said. “But I have to have a better feel, I guess, for what’s around me.”

Helton said he was encouraged that USC cruised to a win despite the errors.

But, he said, “This isn’t a time to get comfortable, this isn’t a time to relax.

“The turnovers and the penalties can cost us against the four remaining teams that we have left to play.”

Jackson chases down record

Cornerback Adoree’ Jackson told his fellow kick returner, Ajene Harris, to get out of the way when California kicked off in the second quarter Thursday.

Jackson knew he was close to USC’s 24-year-old kickoff-return record, held by Curtis Conway.

“I said, ‘Next time, you can have it,’ ” Jackson recounted telling Harris.

Harris stayed out of his way. Jackson returned the kick 22 yards, enough to break Conway’s record. Conway later tweeted congratulations to Jackson.

Jackson said he was informed that he was closing in on the record after USC’s previous game against Arizona.

“That was a shocker,” Jackson said. “I didn’t know I was up there, close enough. I didn’t even know I had enough yardage because too many people were kicking away from me.”

No Davises

During USC’s last loss, a month ago, USC led Utah close late but decided to pull its starting running back, Justin Davis, for the lightly used Dominic Davis.

Helton and offensive coordinator Tee Martin explained afterward that they wanted to rotate their deep stable of running backs. The move was criticized at the time.

USC appears to have shifted strategy. It held a big lead against California and Justin Davis was out with injury, but the Trojans stuck with Ronald Jones II and Aca’Cedric Ware, who each rushed for more than 100 yards, deep into the fourth quarter. Dominic Davis did not appear.

Helton said it had nothing to do with Dominic Davis. He just didn’t want to disrupt the rhythm of Jones and Ware, he said.

“The other two kids were doing a nice job and were in the flow of the game and it just happened that way,” Helton said.

Quick hits

Linebacker Uchenna Nwosu underwent an MRI on his injured knee on Friday. The exam revealed a mild ligament sprain but no structural damage. ... Offensive lineman Chuma Edoga did not suit up for Thursday’s game. Helton said on Friday that Edoga had been suspended for violating team rules. … Helton said defensive end Noah Jefferson, who hasn’t played since the first game of the season due to a shoulder sprain and academic issues, is still at least a week away from returning. … Defensive back Jonathan Lockett left the game with a hip injury.

zach.helfand@latimes.com

Follow Zach Helfand on Twitter @zhelfand