San Francisco Giants (57-49) at Colorado Rockies (38-66), 8:10 p.m.

Probable Starting Pitchers: San Francisco - Madison Bumgarner (11-6, 3.09) Colorado - Jeff Francis (3-3, 5.43)

(Sports Network) - Madison Bumgarner has to be jealous of the run support rotation mate Ryan Vogelsong received in the series opener against the Colorado Rockies at Coors Field.

The San Francisco Giants' left-hander, though, has enjoyed his share of offensive outbursts as well and will take the mound Saturday in the second installment of a three-game set. Vogelsong benefited from a 16-4 outburst on Friday despite yielding four runs and five hits in 6 1/3 innings.

Vogelsong struck out seven and walked two batters to improve to 9-5.

Buster Posey hit a three-run homer, Ryan Theriot and Melky Cabrera both drove in a pair of runs and Brett Pill homered for the Giants, who are in first place in the NL West despite going just 2-7 over their last nine games. San Francisco sits just one-half game ahead of Los Angeles and is two games in front of hard-charging Arizona.

"We don't score like that very often," Giants manager Bruce Bochy said of the season-high in runs. "We were in a pretty good funk there. It was a matter of time."

Posey has driven in 22 runs since the All-Star break and finished with four hits last night.

The Giants, who went 3-7 on its recent homestand, will also visit St. Louis for four games on this seven-game road trip and hope Bumgarner can work on his mediocre road ledger this evening. Bumgarner is 4-5 with a 4.24 earned run average in 11 road assignments this season and has posted back-to-back no- decisions overall.

Bumgarner threw six innings of two-run ball in an 8-7 loss to the New York Mets at home on Monday and is 11-6 with a 3.09 ERA in 21 total starts. The young left-hander defeated Colorado back in mid-April and is 3-3 with a stingy 1.93 ERA in eight career starts in this series.

Colorado has dropped 12 of 15 games and fell to 1-6 on a nine-game homestand with last night's embarrassing loss.

Jonathan Sanchez was on the mound for the Rockies and faced his former Giants teammates for the first time, as he was reached for two runs -- one earned -- in only three innings of work. The bullpen then yielded 14 runs the rest of the way for the Rockies.

"(Sanchez) used a number of pitches through three innings and his command was erratic," Rockies manager Jim Tracy said. "We saw velocity up to 91 mph, but he was still fairly erratic."

Wilin Rosario hit a two-run homer during a four-run seventh inning. The Rockies hope Michael Cuddyer (oblique) can return Saturday after missing the previous three games.

Jeff Francis will try to even this series when he takes the ball for Colorado tonight and is 3-3 with a 5,43 ERA in 11 starts. He allowed five runs and six hits in four innings of an 11-6 setback to St. Louis on Tuesday, and has been reached for 12 runs over his previous three starts.

The left-hander has made 16 career starts against San Francisco, going 7-6 with a 4.83 ERA in 98 2/3 innings.

The Giants have taken four of six meetings with the Rockies this season and went 13-5 in this series a year ago.