In Baseball, why do the batters waiting to go and bat have some kind of cover on their bat? It's not a full cover, it just seems to be something that goes around the thick part of the bat. It looks like a knee/elbow protector that someone has slid over their bat.
He wasn't even swinging at balls or anything, just swinging at air. It seemed almost like he was trying to cover up what was on the bat (like a picture or text)