[KJUmp]

Originally Posted by greymule

From what you describe, I'd say he's legal. It sounds as if the reversal comes after the hand rises from up in front of the chest, an action that doesn't resemble the start of a pitch.

If he makes a forward motion with his arm, something that looks like the start of a pitch, then he can't stop (or reverse, which entails a brief stop).

That was what I couldn't determine from the OP. Sound almost like a HTBT.