EE was riding in the passenger seatof #1 Getman tractor. Operator of tractor hit a rock in roadway it caused tractor to bounce. EE bounced in his seat of tractor and struck his left elbow and forearm on the frame work of tractor. His elbow swelled up & was sore. Finished shift. Came in next day at 11:00 he stated arm hurt. Went to Dr. removed him from work 2 days.