Was sloppy play or over-eager officiating to blame for the deluge of USC penalties?

USC coach Clay Helton stared up at the giant video monitors near the peristyle end of the Coliseum on Saturday evening. Suddenly, his eyes flashed. His body tensed. He began gesticulating running onto the field, gesturing at the video boards.

The screens were showing a replay of a mistake. Arizona quarterback Khalil Tate had fumbled. USC cornerback Jack Jones had picked up the ball with a chance at a big return. But the officials had whistled the play dead.

Helton is almost always polite and restrained. When he yells at referees, he does so discreetly. But the call got even Helton out onto the field, and it earned him, depending on one’s vantage point, a mark of shame or a rare trophy: The officials flagged him for unsportsmanlike conduct.

USC committed so many penalties Saturday that even its coach got one. The deluge of flags was, critics say, a sign of sloppy and undisciplined play 10 games into the season. Or as others contend — including Helton, cryptically — it was a result of over-exuberant officials.

It is possible that both explanations fit.

USC ranks 104th in penalty yardage per game, at 67.0. It averages 7.5 penalties. Even by those standards, Saturday was an outburst. USC totaled 123 penalty yards — its most in a year. USC committed 14 penalties — its most since 2014, when it did so twice. USC hasn’t committed more than that in at least a decade.

Helton declined to give his thoughts on the officiating. Others weren’t restrained by Pac-12 Conference rules. By the third quarter, the student section at the Coliseum lampooned the officials by throwing yellow towels into the air.

In one of the more controversial calls, Jones and defensive back Ajene Harris were called for unsportsmanlike conduct when they pantomimed taking a celebratory photo after a third-down stop. Safety Chris Hawkins was called for pass interference even though he appeared to play the ball and made minimal contact with the receiver.

“I can’t go into those types of opinions,” Helton said. “I’m gonna let everybody have their opinion.”

He did allow that “sometimes you’re gonna get calls, sometimes you’re not. In that game we didn’t get the calls.”

Helton submits questionable or unusual calls to the Pac-12 office for review each week, usually Monday. Helton said he planned to do the same this week.

But many calls were without controversy and hinted at breakdowns in fundamentals.

There were five offensive holding calls, including one on Tyler Vaughns that wiped out a 98-yard touchdown run from Ronald Jones II. USC had three false starts or offsides, plus one more that was declined. One special-teams play ended with a facemask penalty on USC, and another was also declined.

Helton said his penalty was called correctly. He said he was nervous that Arizona would hurry up and snap the ball before the officials could review.

“That’s on me,” he said.

He noted that he did get a review, and USC did end up with the ball. The penalty moved USC from its four-yard line to its two.

“Cost us two yards at the end of the day,” Helton said. “And I’m glad that we got the ball.”

Tight end Tyler Petite and left tackle Toa Lobendahn left Saturday’s game because of injuries, but Helton said they could return without sitting out some more.

Petite exited early and returned out of uniform and with his left arm in a sling. He was diagnosed with a sprain to the AC joint in his shoulder, Helton said. It is the same injury that has limited receiver Steven Mitchell Jr. Mitchell hasn’t started the last two games, but he has appeared in both.

Lobendahn left because of knee pain. Helton said there was no structural damage.

“I’m hoping both are there for Saturday,” Helton said.

Chase McGrath was pulled from kickoffs in the third quarter of Saturday’s game with what Helton described as a groin injury. McGrath continued to kick field goals and extra points, but Helton said, “Some of the longer field goals might have been an issue.” Punter Reid Budrovich handled kickoffs late in the game. … Linebackers Uchenna Nwosu (ankle) Connor Murphy (hip) and Juliano Falaniko (bruised thigh) are all classified as day to day, Helton said.

zach.helfand@latimes.com

Follow Zach Helfand on Twitter @zhelfand