According to Rototimes:
Michael Stanton, RF, Florida Marlins Friday 5/28, 9:25 AM CT
Joe Frisaro, the Marlins' beat writer for MLB.com, speculates that Michael Stanton could be called up by the Marlins at some point between June 5-8.
Our View: The Marlins haven't publicly discussed when they plan on bringing the touted prospect up, but it should come at some point in early June over the next week or two. Stanton will probably start out lower on in the lineup, likely at No. 7, though you have to believe he'll play nearly every day. That would mean either Cameron Maybin or reigning NL Rookie of the Year Chris Coghlan would be bumped from the lineup, though the two struggling outfielders could potentially platoon.
I am adding today given he should be up in 7-10 days. Worth the gamble.