I think it's the Mavs but it could just as easily be the Grizz. I haven't looked at their schedules, whoever has the easiest schedule will probably be the 8th seed.
Not impossible for Phoenix and Dubs to drop down either. West is tough. To solidify yourself as a playoff team you need to be playing .600 ball or better, forget .500 if you can't play better than .500 ball go out East.