Again, due to the cap, Giannis or fox will have to be traded by the time Wembys extension kicks in, otherwise the spurs will have 90-95% of the cap tied to 3 players, with castle due for an extension the year after. Vassell must be unloaded to free up $25m immediately without taking on any long term salary, which is hard to do as Vassell isn’t exactly a hot commodity right now and not many teams are willing to give up 12-13% of their cap for him, unless the spurs are willing to compensate with draft assets.
Trading fox is probably the better basketball move, but optically it would be terrible for the spurs. No one will ever force their way to the spurs ever again.