I'm not convinced that Rosario, by himself, nets the Twins a pitcher who can improve their rotation right now. If I'm wrong, and a #2 who can step into the rotation immediately can be had for Rosario, go ahead and trade him. I don't want the Twins to trade him for another 3,4, or 5 guy. That's trading from a position of weakness to bolster a position of strength. If you trade Rosario for a pitching prospect who profiles better than that but won't be able to step in immediately, what's the harm in waiting?