On 8-25-09 employee exerted extreme force on a long handle wrench to remove a filter. Employee felt slight pain in shoulder not reported until 8-26-09. On 9/09/2009 at 6:30 am employee told supervisor his shoulder still had a slight pain. Physician did MRI and no restrictions on 09/10/2009. Second Physician visit recommended physical therapy that started on 10/06/2009.