USC sophomore Jabari Ruffin, a projected starter at outside linebacker, will miss the season with a torn ACL.
Ruffin (6-foot-3, 240 pounds) played extensively as a redshirt freshman last season, including one start. He was a national top-60 prospect in the 2012 recruiting class and likely would've been one of the better sophomore defenders in the Pac-12 this fall.
The school said Ruffin was injured after being tackled during an interception return, and his injury is a blow at a position that lacks depth.
"This is very unfortunate news about Jabari, but I know he will rehab well and come back strong next year," said coach Steve Sarkisian, per a story posted to the school's website. "And, I know our team will step up in his absence."
USC's new staff plans to use a 3-4 alignment as the base defense, but there will be a lot of mixing and matching in the front seven.
Senior J.R Tavai, who was a defensive end last season, likely will spend most of his time as an outside 'backer this fall. Sophomore Scott Felix (he had been known as Scott Starr until last week; he legally changed his last name from his mother's to his father's) looks to be a for-sure starter, but sophomore Quinton Powell is the only other outside linebacker on the roster who has seen appreciable playing time there. In addition, there are seldom-used junior Charles Burks and true freshmen Uchenna Nwosu, Don Hill and Malik Dorton. The Trojans have good depth at the inside linebacker spots, so it's possible someone like Lamar Dawson could spend some time on the outside.
There isn't much time for the new linebacker group to jell, as the Trojans open with Fresno State before traveling to Stanford in Week 2.
Mike Huguenin can be reached at firstname.lastname@example.org. You also can follow him on Twitter @MikeHuguenin.