You didn't mention how long this dog has been with you, but if he's had a couple weeks or so to settle I'd recommend teaching him the behavior you'd like to see. My puppy, now almost 10 months loves to play fight with me, and she can get pretty rough sometimes too - I bleed almost daily LOL!
But I've tought her a "stop" command and she stops immediately if I tell her to. Of course, sometimes even though it hurts I'm laughing too hard to give the command...hence the blood.
Enjoy your dog, and thanks for rescuing him!
It's not the size of the dog in the fight, it's the size of the fight in the dog. Mark Twain