Well, he is going to be playing a different role in Brooklyn. He won't be the primary scoring option or ball handler so his FG% should improve. However, since he is playing with Brook Lopez and Kris Humpries, his rebounding numbers will probably decline. HIs assists should improve by 1 or 2.
I'm looking at maybe 17-19 ppg, 45-47 FG%, 5-6 apg, 3-4 rpg, 1 spg, and .5 bpg.
Not superstar numbers, but should be consistant and more efficient.