The Brewers selected Miley's contract from Triple-A Colorado Springs on Tuesday.
Oliver Drake was designated for assignment to make room on the Brewers' 40-man roster as Miley is slated to start against the Reds on Wednesday. The 31-year-old put together a strong spring training before suffering a groin strain as he attempted to crack Milwaukee's Opening Day roster, and now takes over Brent Suter's spot in the rotation.