The 21-year-old left-hander is currently on a throwing program, and he is expected to start off in extended Spring Training in Jupiter, Fla., in a week to 10 days.
When fully recovered, Heaney is expected to be part of Class A Jupiter's rotation. Heaney, who was in big league camp, aggravated his lat muscle in the first few days of Spring Training.
Heaney, a standout at Oklahoma State University, made six Minor League starts and pitched in the playoffs for Class A Greensboro.
At the Major League level, Miami is down two starting pitchers due to injuries. Nathan Eovaldi and Henderson Alvarez are both on the DL with right shoulder inflammation.
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter