The Giants placed Gage on the 15-day IL on Saturday due to a left elbow strain, Justice delos Santos of The San Jose Mercury News reports.
Gage previously spent time on the IL in early June due to a knee issue, and he's now set to be sidelined with an elbow injury. The lefty reliever threw a season-high 51 pitches over 1.1 innings against Colorado on Friday, so that's presumably when the injury occurred. Spencer Bivens has been called up from Triple-A Sacramento to take Gage's spot in San Francisco's bullpen.