Glenn Dorsey will miss the entire 2014 season with a torn biceps.

Dorsey was an instant success for the San Francisco 49ers at nose tackle last season after being a relative disappointment during his time with the Kansas City Chiefs after being the No. 5 overall pick in 2008.

Dorsey injured his left arm at practice Friday and left the field after being attended to by the training stuff. He will have surgery Monday.

Dorsey was hurt on his 29th birthday. He is set to be a free agent after this season.