While Rany makes a good point, there is also the counter argument (which I think is at least as persuasive) that starting pitchers need to keep starting somewhere. When you pitch in relief, you usually use only your best two pitches. When you start, you have to use your entire pitch complement. I think that practice using all of his pitches, and dealing with having to face batters multiple times in the same game is useful. And if they plan to put him right back into the KC rotation the next time they need a fifth starter, I can see why they’d want to keep him on a starter’s schedule, rather than the inconsistent pitching schedule of a reliever.

But I still think the Rany/Warden argument of “He’s got nothing left to prove in AAA,” is simply short sided.

Having nothing left to prove does not equal ready to help the ML team win games. If this move wasn’t a simple move to get a bullpen arm up for 2 weeks it would still make sense to send down a player that wasn’t performing at the MLB level, even if he had dominated the level below if the MLB team was not in a position to raise the white flag of defeat every 5th day while he ‘figured something out’ at the MLB level since they are seemingly in a close division race.