On 9/11/11, employee was rolling a 2 yd mucker tire in shop, when tire hit divot in ground & it made the tire spin & fall into his Left knee. He went to medic for evaluation. all was ok. no days were missed. In November, employee went to doctor cause knee was still sore, surgery was set for 11/18/11, 1st shift missed was on 11/22/11.