I think Sheed is actually retired, which means he can't come back for a year. However, even if he wasn't, I would put the chance of him returning this season at less than zero.
I believe Sheed had some love for the game of basketball. But I also believe he had a lot more love for money, and pride. For him to give back a significant amount of money in a buyout, and then come back and play for the vet minimum is just against his code of ethics. He believes he should be paid what he is worth, and he certainly is not going to get himself into game shape for the vet minimum.