Through three games, USC has relied mainly on quarterback Matt Barkley and receivers Marqise Lee and Robert Woods to produce the vast majority of its yards and points.
Meantime, the Trojans have rushed for only 121.7 yards a game, which ranks 93rd among 120 major college teams. USC has completed 69 of 112 passes for 835 yards. The Trojans have rushed 84 times for 365 yards.
Stanford limited USC to 26 yards rushing in its 21-14 victory last week.
Senior tailback Curtis McNeal anticipated that the focus would be on the passing game — "When you have a big-time quarterback and big-time receivers, you have to expect that," he said Tuesday — but he expects the rushing attack to become a larger component of the offense.
"It will have to," he said. "That's the only way we're going to win. We can't just depend on Barkley and Marqise and Woody all day to make plays.
"Other guys on the team have to step up."
USC, which fell from No. 2 to No. 13 in the Associated Press poll, plays California in a Pac-12 Conference game Saturday at the Coliseum. The Golden Bears have given up 154 rushing yards per game.
McNeal, who rushed for 1,005 yards last season, has gained 110 yards in 23 carries. He noted that he must read blocks better and run without hesitation.
Silas Redd, who gained 1,241 yards last season at Penn State, has rushed for 180 yards and three touchdowns in 37 carries.
Both McNeal and Redd were sidelined briefly against Stanford because of injuries, but both returned.
Redd, after fumbling during a training camp scrimmage and again against Stanford, said that a "stinger" condition caused his arm to go numb.
"I just lost feeling," he said Saturday. "So I went to brace my left arm and I dropped the ball."
USC Coach Lane Kiffin said that he was "very concerned" about Redd's condition — and the fumbles.
"It's happened twice and, obviously, taking care of the ball is very important to us," he said. "We're looking at everything that we can."
With McNeal and Redd unavailable at times against Stanford, fullback Soma Vainuku moved to tailback.
Redshirt freshman Javorius Allen did not play and sophomore D.J. Morgan is sidelined after knee surgery.
Aundrey Walker acknowledged that he was upset by Kiffin's decision to open competition for the left tackle spot, but noted optimistically, "it's nothing but motivation to get better."
Freshman Max Tuerk is excited about the opportunity. "I just have to work my butt off every single day and compete day in and day out," he said.
Kiffin said Walker played "pretty good" in the first half against Stanford, but called his second-half performance and effort lacking.
"Guys are going to get beat, guys are going to drop balls," he said. "But we won't tolerate lack of great effort — not when you put on these jerseys that all these great players have worn before.
"I think Aundrey is going to respond well to this."
Senior Abe Markowitz said he would be ready if called upon to play center or guard against Cal. Redshirt freshman Cyrus Hobbi started in place of injured center Khaled Holmes against Stanford. ... Punter Kyle Negrete was one of 22 players selected nationally to the Allstate AFCA Good Works Team, which recognizes college football players for community service. Negrete participated in humanitarian aid missions to Nigeria and Haiti and also started a "Best Buddies" program at the University of San Diego that linked football players with autistic children.