Johnson (toe) was optioned to Triple-A Pawtucket on Thursday.
Johnson was able to make it back to the mound this spring following an elbow issue from last August, but his quest to make the Major League roster was derailed once again due to a mid-March toe injury. Look for the left-hander, who saw 4.1 innings in the majors last season, to operate at Triple-A until his performance or injuries on the big league roster dictate a callup.