San Francisco returns home after a 3-4 road trip to start the season. The champs closed their trek in disappointing fashion on Sunday, as they fell to the San Diego Padres, 6-4.
Buster Posey hit a solo home run while Brandon Belt, Gregor Blanco and Matt Duffy each drove in a run for the Giants, who also got two hits and a run scored from Nori Aoki. Jake Peavy (0-1) allowed four runs on four hits with three walks and five strikeouts in four innings of work.
The Giants dropped three of four to the upstart Padres.
Getting the call for the Giants on Monday will be righty Chris Heston, who was impressive in his season debut on Wednesday versus Arizona. Thrust into the rotation due to an injury to Matt Cain and Peavy's balky back, Heston shined, scattering three hits over six scoreless innings.
"I'm just on cloud nine right now, ecstatic that I was able to come in here and help out," Heston said.
Heston will be just the second rookie in San Francisco history to start a home opener.
"That's one of the best places in baseball to play on a regular day, so with a little added excitement out there I think it's going to be electric," Heston said.
Colorado, meanwhile, will turn to righty Eddie Butler, who did not get a decision on Wednesday in Milwaukee. Butler surrendered two runs and four hits over 5 2/3 innings of that one, but didn't factor in his team's 5-4 win.
The Rockies have been one of the bigger surprises in baseball in the early going, as they have won four of six to start the year. Colorado, though, lost two of three to the Chicago Cubs, including a disappointing 6-5 setback on Sunday.
DJ LeMahieu tripled in three runs for Colorado, as the second baseman continues to swing the bat well from the bottom of the lineup. He's hitting 12-for-25 on the season, having split his time in the No. 8 and 9 hole.
"We didn't play very clean, but we certainly got into position to win that game," Rockies manager Walt Weiss said.
Colorado was 10-9 versus the Giants last season.