Miley was lights out last season when he came back. Rode him to a fantasy baseball title in a 30-team league where he surprised everyone with consistently excellent game day starts. He started 16 times and had 6 quality starts, never giving up more than three earned runs in any of his starts last season. It could be an outlier season for him... or it could be the point where he's turning the corner.
the Brewers had the bullpen to yank Miley early, which kept him out of trouble. If a lot of chips fall right (Barraclough, Rosenthal being OK and Suero / Glover / Grace are on form), then it might work well. But that's a lot of ifs. It's as much of an if as "if Joe Ross is OK" or "if Fedde's stuff comes back."