was.
"A player attempting to catch a forward or backward pass, or a player who has completed the catch but hasn't had ample time to protect themselves or hasn't clearly become the ball carrier yet."
If he had dropped the ball, would it have been a catch? No, it would have been in incomplete pass. He was still in the process of catching the ball. He hadn't even turned around to move up field. He was in the process of turning when he was hit. It was an obvious blindside hit.