LOS ANGELES -- Leading rusher Vavae Malepeai is unlikely to play for No. 13 USC in the Pac-12 championship game against Oregon on Friday night.
USC coach Clay Helton said Wednesday that Malepeai sprained a ligament in his knee during the unbeaten Trojans' 43-38 victory over UCLA last weekend.
"Vavae is probably not playing in this game," Helton said. "He has not practiced this week. Does not look good for the game going in."
USC (5-0) probably will have to play for its third win in 13 days without the senior tailback, who leads the Trojans with 238 yards and three touchdowns this season. Malepeai rushed for a season-high 110 yards against the Bruins but sprained the medial collateral ligament in his knee late in the game.
Malepeai has 1,503 yards rushing and 17 touchdowns for the Trojans over four seasons marked by injuries but also excellent stretches.
USC has relied heavily on Kedon Slovis and its passing game this season in coordinator Graham Harrell's version of the Air Raid offense, leaving the Trojans last in the Pac-12 with just 109.2 yards rushing per game. Oregon's rushing defense is only ninth in the Pac-12, giving up an average of 184.2 yards per game.
Still, Tailback U. is quite deep at the position, and Helton says he expects sophomore Markese Stepp and senior Stephen Carr to take more prominent roles against the Ducks (3-2).
Stepp has 140 yards and two touchdowns in four games this season, and the 235-pound runner provides an approximation of Malepeai's physical style. Stepp's 2019 season ended after only six games because of an ankle injury that required surgery, and he spent most of the offseason rehabilitating from that injury and then dealing with a case of turf toe.
Stepp had only one carry against UCLA, but it was a gritty 2-yard run on third-and-short to keep alive a drive that ended in a go-ahead touchdown for USC in the fourth quarter of its comeback win.
"I think Markese is on the verge of exploding," Helton said. "It has not been the easiest of roads in dealing with an injury, especially the one he had, at running back. ... I can't wait to watch him play. I know he's looking forward to it. It's neat to see his enthusiasm and how excited he is for this week. I think he's right on the verge of doing something special, and we need him to."
Carr, who has also had numerous injuries in his USC career, has 136 yards rushing and two touchdowns this season. USC also has sophomore track star Kenan Christon, who has had only 10 carries this season.