Pretty much what Michigancat said. If Brad fails at the NBA level, he can still fall to the high major college level. If he jumps to the high major college level and fails, well what's left besides Butler-like schools? Smart move by him.
Also it's no secret that Self wants to return to OSU. I have heard from 2 sources that he has said, without a doubt, he will coach there at some point. As Bilas (I think? maybe Gottlieb or Parish) said, he'll go to the NBA at some point and come back to OSU. Spurs makes the most sense.