While inspecting a rail car, EE pulled right shoulder. At the time, EE did not feel anything was wrong with shoulder. EE decided to see a doctor on 4/11/05. Doctor released EE to work, no restr. & scheduled MRI. Specialist reviewed MRI, diagnosed a rotary cuff injury on 5/10/05. Employee released back to work, restricted duty, until surgery on 5/26/05.