Bumgarner (14-10, 3.15 ERA) has struggled as of late, taking the loss in his last three straight starts, though has been very successful against Colorado in his career. The big left-hander has a 0.66 ERA in his last four outings against the Rockies, allowing two runs or fewer in each of his last seven starts, winning the last three.
One man Bumgarner will have to be careful with is Carlos Gonzalez, who is batting .368 with two homers and two doubles in 19 career at-bats at Coors Field against Bumgarner.
Colorado will send out Jhoulys Chacin (2-5, 4.50), who has been solid since returning from a three month DL stint, though without much allowing no runs on seven hits in his last start, though was still pulled after 3.1 innings en route to a 1-0 loss to Atlanta. He has a 5.40 ERA in his last three starts against San Francisco, all of them loses.
Chacin has struggled with Pablo Sandoval in the past, who is currently 7-14 with two homers, a double and a triple against the Colorado right-hander.
The Rockies are 2-5 against the Giants at Coors Field this season.
First pitch is set for 5:40 p.m. PT with coverage on CSN Bay Area and KNBR 680 AM.