From the Times Union’s Sports Desk:

Skip ahead to 0:46 so you can catch the AMAZING transition effect~!

On the replay, it looks like it was Hanks landing a hard and straight left to Pedro’s shoulder that dislocated it. I remember that punch and I thought Hanks had completely whiffed on it, but it looks like it hit flush on the ball of the shoulder. Which, well, that’ll do it.