Johnson is the scheduled starter for Triple-A Pawtucket on Saturday.
The Saturday slot puts Johnson right on schedule for a potential callup to pitch for Boston next Friday, the next time the Red Sox will need a fifth starter. Boston will need a starter after the team placed Eduardo Rodriguez (knee) on the 10-day disabled list Friday. The left-hander experienced a subluxation of the ligament in his right knee following a stumble in the bullpen prior to Thursday's game in Baltimore. If Johnson comes out of Saturday's start without issue, he's expected to make his third start for the Red Sox next week.