Johnson recently left the Red Sox's alternate training site in Pawtucket and returned home to Florida, Christopher Smith of The Springfield Republican reports.
Johnson nor the team has provided an explanation for his departure, but sources familiar with his situation believe the 29-year-old may opt out of the 2020 season. The southpaw most recently tossed 5.1 innings in a simulated game Friday and was viewed as a potential option for the big-league rotation, but his lack of a 40-man roster spot may have hindered his chances of receiving a callup.