USC running back Joe McKnight missed more practice this weekend with another injury.
According to coach Pete Carroll, McKnight suffered a hyperextended right elbow in a scrimmage at the Coliseum on Saturday and sat out Sunday's practice with a near full-length brace on his arm, the Los Angeles Times reported.
Carroll told reporters after practice McKnight could miss several more workouts but downplayed the injury.
"It's not damaged or anything like that," Carroll said. "I don't think it will be but a couple of days."
McKnight was expected, along with junior Stafon Johnson, to spearhead USC's ground game after showing promise as a freshman.
McKnight, a 6-foot, 200-pound sophomore, is among a cadre of six talented running backs vying for playing time with the Trojans.
McKnight ran for 540 yards on 94 carries for a 5.7 per-carry average in 2007, when he rushed for three touchdowns.
The Trojans also used him extensively as a receiver last season, when he caught 23 passes for 203 yards and a touchdown.
This summer, McKnight was sidelined for parts of other practices after a teammate accidentally closed a door on his right hand, fracturing the tip of a finger and slightly injuring another, the Times reported.
He has also missed practice with a skin irritation.
The Trojans, ranked No. 3 in AP's preseaon poll and No. 2 in USA Today's coaches poll, open their season at Virginia on Aug. 30 before a highly anticipated showdown against Ohio State (No. 2 AP, No. 3 USA Today).
They host the Buckeyes Sept. 13.
McKnight declined to comment to the Times on Sunday.
"It's unfortunate, Joe keeps coming up with something," Carroll said, according to the Times. "He has missed a lot of practice already and it's killing him. He hates the fact that he has. The fingers are fine, he's ready to go, but something else popped up."
Information from ESPN.com's Ted Miller was used in this report.