My guess for next year would be 14/7/6
I think the assist number will go down as the team gets older and the offense slumps a little. This will, however, lead to him being asked to take a bigger role, and his jumpshot will get better over the summer. Rebounds up a little too, thanks to increased playing time.
Super optimistic me says 16/10/7 with increased playing time, but I'm going to tell super optimistic me to go back to watching the Tim Duncan-lead C's.