Do you trade Rudy to a title hopeful in the east (Boston, Brooklyn, Toronto)? Trade him to a random team in the east for assets you can get (Atlanta, New York, Orlando, Charlotte)?
Trade Rudy to Golden State for Wiggins just to watch the league burn next year?
The trouble is Mitchell doesn't have the salary to bring much back other than draft compensation but is young enough to try and stick with long term, while Rudy brings more value than you can possibly get back from another team (look at what Drummond went for at the trade deadline).
If there are problems and you force them to play together, you either get Donovan forcing a trade or Rudy walking next summer.