EMPLOYEE WAS SITTING ON A SUPPLY CAR AS IT WAS BEING PUSHED. THE PROP SETTERS ON THE CAR STRUCK A 3"" WATER LINE COUPLER AND MOVED ON THE CAR HITTING HIM ON THE RIGHT KNEE. MIKE COMPLETED ACCID ENT REPORT ON 8-7-00 AND WENT OFF WORK DUE TO CONTINUING PAIN IN HIS KNEE.