The Giants optioned Bivens to Double-A Richmond on Tuesday, Shayna Rubin of the San Francisco Chronicle reports.
He's making room on the active roster for right-hander Hayden Birdsong, who was called up from Triple-A Sacramento to start Tuesday's contest versus the Nationals. Bivens has managed a 1.99 ERA and 18:6 K:BB over 22.2 innings with the Giants, although he has served up five home runs.