T.J. McDonald already leads USC in tackles.
Now the senior safety, a team captain, also has taken it upon himself to help lead the Trojans out of their position as the most penalized team in major-college football.
USC, which plays at Arizona on Saturday, has averaged 9.86 penalties a game.
"They haven't hurt us too bad so far," McDonald said Wednesday, "but down the road you get these tough games coming up, that's something that we can't have and we've got to eliminate."
USC Coach Lane Kiffin has said that, in regard to penalties, he hoped the Trojans "hit rock bottom" in the first half of last week's game against Colorado.
He also noted that team leaders have for the first time stepped up to take an active role in alleviating the problem.
"I think before we weren't even saying anything," McDonald said. "Everybody makes a mistake during games and you don't want to say much.
"But we're saying it throughout the week. ... They know that if we're not tolerating it as a team, as players on the field, it's something that can help us down the road."
McDonald, suspended for half of a game last season for making an illegal hit against Stanford, has offered counsel to freshman defensive tackle Leonard Williams, who was ejected from the Colorado game for a flagrant personal foul.
After reviewing the incident, the Pac-12 Conference did not suspend Williams, who said he was spit on by a Colorado player.
"It just happened so quick," he said. "I wasn't really thinking. I can't take it back. What's done is done and I'm just trying to move forward."
Kiffin said Williams apologized to the team Saturday.
"It was a learning moment for a true freshman," Kiffin said. "I can't imagine it ever happening again."
"I just won't let that happen again," he said.
Special-teams coach John Baxter deferred to Kiffin when asked about the decision to have Cody Kessler wear No. 35 in the first half against Colorado.
Asked if Kessler, who has worn No. 6 since last season, might wear a different number again this season, Baxter said, "That's between our staff and the equipment room."
USC announced that receiver De'Von Flournoy will now wear No. 80, defensive back Ryan Henderson No. 14, walk-on fullback Hunter Simmons No. 42 and walk-on running back Robert Mojica No. 40.
Barkley wins scholarship
Quarterback Matt Barkley is among 15 winners of the National Football Foundation National Scholar-Athlete Award.
The award includes an $18,000 postgraduate scholarship.
Barkley, who graduated in May and is taking one class this semester, compiled a 3.21 grade-point average in communications.
Barkley is a finalist for the William V. Campbell Trophy, awarded to the top scholar-athlete in college football. The winner receives an additional $7,000 scholarship.