Johnson suffered a tibial stress fracture and is out for the next 5-to-6 months after undergoing surgery, Joe Frisaro of MLB.com reports.
Johnson was nabbed by the Marlins with the 53rd pick of the 2018 first-year player draft, but it'll be a while until he's back in action. He advanced to Low-A last season and hit .188 with two homers and six RBI over 23 games. Johnson figures to be ready to return in either August or September of 2019, barring any major setbacks.