Well, I think you can pencil Ryan and Ober in to the starting rotation for next year. If they can resign Pineda to a fair deal, that makes 3. I suspect that Griffin Jax will at least start next year in the rotation - but my gut tells me he may not finish the year in the rotation.
I do not want to see any more of Dobnak, Thorpe, Smeltzer or any of the other AAAA pitchers.
So, I would say the Twins need to go out and trade for or sign free agents to fill at least one and probably two spots in the rotation for next year. I don't expect them to throw out huge deals, but at least something a rung above Happ or Shoemaker.
Then, it all gets down to the players who were injured in the minors this year to see how they develop/stay healthy. I would not be surprised if Balazovic is in the rotation by mid-year.