Coonrod was optioned to Triple-A Sacramento on Tuesday, Andrew Baggarly of The Athletic reports.
The right-hander was called up to serve as the 26th man for the Giants' doubleheader Monday against the Rockies, and he ended up pitching a scoreless ninth inning in the first game with San Francisco leading 19-2. He carries an ERA of 7.42 at the Triple-A level this season.