The team announced Thursday that Bars, a redshirt junior, will undergo surgery in the next few days. Bars then will begin a rehabilitation of four-to-six months, according to team doctor Peter Seidenberg.
The 6-foot-3, 251-pound Bars was listed as a backup to C.J. Olaniyan on Penn State's summer depth chart. He appeared in eight games last season, recording two tackles.
A two-time academic All-Big Ten selection, Bars redshirted in 2010 and has one season of eligibility remaining. Redshirt freshman Evan Schwan likely will step into the backup role.