I can't envision at all in my head what this looks like. An underhand flip doesn't sound as bad. I was imagining him rearing back and throwing his bat at the ump with all his might. That's what I was thinking. I have no idea if this is the case, but I've seen a few times where a player would flip his bat, with the intention of catching it, after being rung up. I wonder if that's what Delmon tried to do, but it slipped or whatever. I have no idea though, to be honest.