The Giants placed Gage on the 15-day injured list with knee inflammation Wednesday, reports Susan Slusser of the San Francisco Chronicle.
Gage (knee) last appeared Monday against Milwaukee and had a rocky inning of work, allowing two earned runs on three hits and two walks. The knee issue may have contributed to the struggles, as he commands a 2.63 ERA, 1.29 WHIP and 19:13 K:BB through 24 innings on the season. San Francisco called up Dylan Smith to take his spot on the active roster.