I really don't agree. First of all, Berrios is only 21. I do believe he's the Twins best pitching prospect, at least in the top two levels, but I don't know how he would fare in the majors. Further, I believe the Twins will want to protect him and not use him for too many innings. He's never really pitched out of the bullpen, so that may have been an issue. Finally, there are service time and 40-man issues. Hindsight is 20-20, but it may be that they promoted the most ready guy (Duffey) and adding two to the 40-man was thought to be too many. The May thing didn't work out. I'm guessing the Twins would have kept May in the rotation if Duffey got knocked around, but since he did well his second (and now third) start, they kept May as a bullpen option.