Gearrin threw a scoreless inning in a rehab outing on Monday for Triple-A Sacramento, Alex Pavlovic of of CSN Bay Area reports.
If his rehab continues to go well without any setbacks, Gearrin is expected to rejoin the Giants at some point later this week. Gearrin won't likely pitch in many high-leverage situations with the recent acquisition of left-hander Will Smith from the Brewers.