Employee was installing damper liners in the #2 finish mill seperator while lying on his side getting a 50 lb. liner into position with another co-worker. EE strained his left shoulder. Injury occurred on 9/12/06 & was reported on 9/21/06. The EE chose to do home care at the time & then requested to go to the Dr. after the pain persisted. EE was given restrictions.