McGough was designated for assignment by the Marlins on Thursday, Joe Frisaro of MLB.com reports.
The right-hander will be removed from the 40-man roster to clear a spot for Eric Jokisch, who was claimed off waivers from Chicago on Thursday. McGough will likely remain at Triple-A New Orleans, where he's allowed six hits and four earned runs over 2.2 innings thus far in 2016.