Milbrath was sent from Cleveland to Miami in exchange for Nick Wittgren on Monday.
Milbrath didn't have much success in his first taste of Triple-A action last season, posting a 5.93 ERA with a 12:8 K:BB for Columbus. In a longer, 50-inning sample with Double-A Akron, he produced a solid 3.42 ERA, but that's not particularly impressive for a player who is now 27 years old.