Penn State defensive end Pete Massaro will miss the 2011 season after tearing the ACL in his left knee in Friday's practice.
Massaro started the final 11 games for the Lions last season and was in line to retain the job before the injury.
He will undergo surgery in the next two to three weeks and undergo about nine months of rehabilitation, according to team doctor Wayne Sebastianelli.
The redshirt junior missed the 2009 season after tearing the ACL in his right knee during Penn State's spring game.
He returned last fall and recorded 37 tackles, 3.5 sacks, one forced fumble and one fumble recovery. Massaro redshirted in 2008.
Adam Rittenberg covers Big Ten football for ESPN.com. He can be reached at firstname.lastname@example.org.