When laying down 5” drill pipe, the Derrickman was operating the rig floor winch lowering a joint to the catwalk. He stopped lowering the joint when he saw a co-worker walking on the Catwalk towards the V-Door. The coworker was bringing a drum with drill pipe pin protectors that were to be picked up to the rig floor. When the co-worker got next to the hanging joint on the winch line, he pushed the joint of drill pipe aside, thus causing the drill pipe pin end to fall off the Catwalk. When the pin end fell off the catwalk, the joint of drill pipe struck the injured worker on the right shoulder.