Wacha will start Wednesday against the Giants, Jim Hayes of FOX Sports Midwest reports.
Wacha will be pitching on short rest -- his last start came Saturday against the Reds -- so he likely won't be asked to pitch too deep into the game. The right-hander has been solid across four starts since rejoining the rotation in mid-August, posting a 3.05 ERA, 1.16 WHIP and 22:7 K:BB in 20.2 innings.