USC senior defensive end Devon Kennard is likely to miss the 2012 season after tearing a pectoral muscle during a weight training session on Thursday, sources confirmed to CBSSports.com.

Kennard, a 6-3, 260-pound senior from Phoenix, started five times and made 29 tackles as a 2011 junior and was expected to play a key role on the line for the Trojans this season.

Instead, he'll likely have surgery and take a redshirt year. If that happens, he will be eligible to play again in 2013.

The loss would be especially significant to USC because its defensive line is perhaps its thinnest unit, with new starters set to debut at both interior tackle spots and, now, possibly at Kennard's end spot.

USC's depth concerns are further complicated by the 75-man roster limit set for it as a result of NCAA probation. 

The Trojans may turn to little-used junior Kevin Greene to fill in for Kennard, or perhaps highly-touted incoming freshman Leonard Williams. Redshirt freshman Greg Townsend, Jr., and junior college transfer Morgan Breslin are also options.