The Manu uncertainty is part of the reason WHY the Thomas/Salmons trade needs to happen. Personally, I think the two are mutually exclusive. Like anyone else, I'd love for Manu to stay. I just think he's going to test his value in free agency and will likely get a contract worth more than the Spurs can pay. I simply think he wont be back.
Salmons would help hedge against the loss of Manu. The colossal failure of the RJ trade also makes getting another swingman, of good all-around ability, a priority.