Having a guy like Duffey in the pen gives the Twins the luxury of trying out new pitchers like Mejia. It also gives them the luxury of working Hughes and Gibson back to form, assuming we see Gibson again this year. If Duffey goes to the rotation and those two end up in the pen, that luxury is lost. The Twins will no longer have the reliable bullpen arm to back up a starter who had a bad day or a starter who needs more time to get into form. Do you expect Hughes to be able to take on that role? What you are suggesting will make the team weaker. Also, I think it might be a stretch to say Duffey is better than Santiago. At best they are about even. Duffey has two pitches, and unless they invent a steel arm for him he is going to be tired by the time he faces a lineup for the third time in a game. Like all one- and two-pitch pitchers, he has to throw hard. He can't pace himself as much as pitchers with a larger arsenal can. The Twins always planned for him to be a reliever, he only started in the first place because there were no other options and he was, for a while, doing a good job.