This is a great question. The only way I can see NOT getting Sheed is because at San Antonio he'd be a starter.
What would I do? If that's what it takes, sit Perk. But in my opinion, I think Sheed has to be sold already. I have trust in PP, KG, RA, DA, Doc and Wyc. If these guys want him this bad, then Sheed must be a pretty good guy as well as a very good player. If he really is a good guy he'll know that Perk should start.