Justme,
Yeh I watched, and yeh I asked my son (pitcher) what he thought, he said it was a legal delivery.
Question: If this is a legal move, what rule would you use to defend it? I don't get it (not the first time).
Seriously though, if it is a legal pitch, what would stop a guy from taking a "step" before he throws? Or getting a running start (ie. Cricket hurler) as long as you touch the rubber on your way to the plate?