My feeling, which I've never tried to study systematically, is that when teams trade for a stud prospect, they try to lessen the pressure on that player by making the trade be for other pieces who will help right away. That gives the team's marketing department something positive to say while the young guy is still developing. Supposing that the Twins could pry away Urias for Dozier plus ESan plus two good prospects, I'm not sure it would be good for Urias's development, unless he is of an extraordinary makeup. A lot of pressure on someone in his early twenties. Even though he does have a year under his belt now. So, as regards the AJ trade, I recall Liriano as the difficult piece to get the Giants to include. But he was not MLB ready, making his trade value lower, so it was possible to package him with other players for AJ. Nathan was available as a failed starter, and the Twins were not thinking outside the box to put him in the 'pen - the Giants had already done so for a year. It was a good trade for both sides, except the Giants bollixed up their end of the trade in conjunction with AJ's allegedly prickly personality. Getting a really good reliever with big league experience is a whale of a lot easier than getting a really good starter with big league experience. Nathan wasn't the centerpiece. Nathan was the marketing piece. He turned out well. As for going after the next Arrieta or Kluber, that's good too. An all-of-the-above strategy for finding talent is better than one true way. The problem with finding the next "pony in the pile" is that it consumes a lot of roster space, which in many ways is the ultimate scarce resource. You don't just find Arrieta and say "there, done", you acquire several like him continually and use the 25-man to sort things out. In fact, finding such guys was apparently Terry Ryan's fond dream with all his make-good contract offers, and whether by bad luck or bad design (signing rather than trading) or bad scouting it just never seemed to pay off for him.