Miley sustained right oblique strain in Tuesday's start against the Indians, Adam McCalvy of MLB.com reports.
Miley exited in the first inning of the game after throwing only 19 pitches. It's a tough break for the 31-year-old in only his second start of the season after he sustained a groin strain in spring training. No timetable has been announced, but a trip to the disabled list seems likely with Brent Suter -- who relieved Miley on Tuesday -- the top candidate to slot into the Brewers' starting rotation.