San Francisco 49ers linebacker Scott McKillop suffered a torn ACL and patellar tendon in his left knee, Matthew Barrows of the Sacramento Bee reports.

A fifth-round pick out of Pittsburgh in 2009, McKillop was active for all 16 games as a rookie, finishing second on the team with 15 tackles on special teams and a fumble recovery. McKillop added four tackles in limited action on defense.

The 6-1, 244-pound inside linebacker was expected to see a lot of playing time this summer as 33-year old Takeo Spikes will be on a limited practice schedule to ensure he's ready for the regular season.

With McKillop lost for the season, veteran Matt Wilhelm and 2010 third-round pick Navorro Bowman will compete for the #3 inside linebacker job.