Johnson was outrighted to Triple-A Sacramento on Tuesday, Henry Schulman of the San Francisco Chronicle reports.
Johnson (concussion) was reinstated from the 7-day disabled list Thursday and tossed three scoreless innings for Double-A Richmond.
Johnson (elbow) was optioned to Triple-A Sacramento on Monday, Henry Schulman of the San Francisco Chronicle reports.
Johnson underwent Tommy John surgery last week, Alex Pavlovic of NBC Sports Bay Area reports.
Johnson was placed on the 7-day disabled list Sunday, Henry Schulman of the San Francisco Chronicle reports.
Johnson -- who made a successful switch to a reliever last season -- is expected to continue in that role this season, CSN Bay Area reports.
Johnson was added to the Giants' 40-man roster Friday, Alex Pavlovic of CSN Bay Area reports.