Taking Castillo as an example, having him at $25M and Tucker at let's call it $40M, the team next year is already at ~$230M.
Tom would have to significantly change his spending habits or Jed would be backed into a corner *having* to trade a salary to do anything beyond minor roster tinkering. Not impossible, Theo did it for Darvish, but I feel pretty comfortable saying this is one of those places where Jed and Theo have different sensibilities.
Edit: Actually I think that $230 might be if Shota leaves, so more like $245M as a starting point.