With Houston apparently trying to get Randolph from the Grizzlies, it seems likely that they will have to trade a couple of the power-forwards to clear enough space. Memphis has a lot of bigs, and I doubt they'd really want three or four more on their roster. If Minnesota is looking for bigs, Houston seems like the best trade partner. The thing is, Houston won't have the cap space to take both Randolph and Williams without finding a way to move Asik or Lin. So if Memphis doesn't want Williams, then the Wolves will have to look for a fourth team to take him.
Enter the Spurs? Possibly. They have the guards and expiring contracts to fill the Grizzlies' coffers enough to make the numbers work. If they can find a fifth team to take Blair (or if the Wolves want him), then facilitating the trade should be easy:
http://espn.go.com/nba/tradeMachine?tradeId=axfr52o
Something like this could certainly go down. It's probably more likely that team like Phoenix plays the fourth-team role and just take Williams for nothing. But I imagine that Williams' value is at an all-time low right now, and Bonner, Neal and a first (probably to Memphis) really seems like fair value if the Wolves get the big(s) they want from Houston.