Emp was moving a 3""X7' shaft (approx. 180 lbs). Later he noticed tenderness in his lower abdomen. He went to the clinic the next AM, evaluated by the nurse & given OTC meds. On 4/23 he was seen by the co. dr. The PM of 4/23, worker returned to the clinic with extreme pain & was referred to a 2nd dr., which he saw on 4/28. He was then placed on modified duty pending surgical eval.