Normally I would have agreed that the Spurs draft the international player, stash him overseas, and pick him up later. However, age is a factor now. San Antonio would be better served by trying to add someone now who can produce effectively in the near future. Again, they normally don't plan on adding through the draft, but with Arthur available, that's a real possibility (there is absolutely no way he'll be available to the Spurs during the real draft). Which brings me to the Rockets.
Houston has a number of players in the range of Arthur: Scola, Chuck Hayes, Lampe, and that other fellow, what's his name, oh yeah, Battier. But Ibaka has tremendous "upside," and at only 18 is still growning. Someone like Mutombo would be able to give him guidance in order to get him the basketball maturity that he needs, if the Rockets did bring him over to play in the NDBL.
It just doesn't seem to me that the Spurs will want to go the overseas route again this year.