Sports simulations so far haven't fallen into the trap with Kinect that some did with PlayStation Move (including NBA 2K12, folding in casual motion-control schemes or mini-games that seemed to use a motion controller simply because it was there. If NBA 2K13 is using Kinect, I'd expect this to involve voice commands and very little else. I've not heard anything official but it's reasonable to think Kinect will let you call for a ball or tell a teammate to shoot in the "My Player" career mode, or to change defenses or run a play in any of the team modes. FIFA 13 is already confirmed as doing these sorts of things.
When reached by Kotaku, a 2K Sports representative declined to comment.
Amazon Outs NBA 2K13 As "Better With Kinect" [360Sync.com]