Odds are JR is gonna be rusty this game. He might knock down a couple from downtown, but I'm not expecting too much from him this first game back. He hasn't played forever, probably have a new role (off the bench), and will probably have nerves and will be pressing a bit (trying to make up for letting his team down).
Hopefully I'm wrong, but I don't see a huge game. I'd be happy if he chipped in a semi efficient 10-12 points. The biggest immediate effect is that he deepens/changes our rotations and spaces the floor, which will have a huge impact in itself.