By winning a series against their closest NL West rival, the San Francisco Giants have their biggest division lead of the season.
The Giants will look to tack on to that advantage beginning Monday night when they open a three-game road series against the Colorado Rockies.
After taking two of three from the Los Angeles Dodgers, San Francisco has opened a 5 1/2-game lead in the West.
"This game's obviously bigger because not only is it against our rival in the West, it's the Dodgers, too,'' Zito said. "Being 5 1/2 up, we like where we're at. We certainly can't rest on our laurels. We have to fight every day, and that's something we've been doing all year.''
San Francisco has only one series remaining against a team with a winning record, visiting the Dodgers to close the season. The Giants have seven games left against last-place Colorado (56-83).
San Francisco is 8-3 against the Rockies while averaging 7.2 runs and hitting .307. Posey, who is hitting .361 with seven RBIs over the last nine games, has homered three times in 10 games against the Rockies while batting .412 (14 of 34) with 11 RBIs.
The Giants may need to continue their hot hitting against Colorado with the way Ryan Vogelsong (12-7, 3.29 ERA) has pitched recently.
Vogelsong is 2-2 with a 10.13 ERA over his last five starts. He gave up six runs and nine hits in 3 1-3 innings Tuesday in an 8-6, 11-inning loss to Arizona.
It was the third time in his last five starts Vogelsong failed to make it out of the fourth.
"I thought he had good stuff," manager Bruce Bochy told the Giants' official website. "The pitches might have caught up with him. He was working hard out there and his pitch count got up, and that might have taken a toll."
While the right-hander wasn't at his best in Colorado last month, he won his fifth straight decision against the Rockies, giving up four runs in 6 1-3 innings of a 16-4 victory Aug. 3.
Vogelsong has a 1.80 ERA in six career starts versus Colorado.
He'll try to get back on track against a Rockies club that has dropped five straight after being swept in a three-game series at Philadelphia over the weekend. Colorado lost both ends of Sunday's doubleheader.
The Rockies couldn't protect a 4-1 lead in the nightcap, committing a season-high five errors in a 7-4 loss. Catcher Wilin Rosario had four passed balls in the opener.
"It's young people,'' manager Jim Tracy said. "If they're going to learn, it won't be in 9-1 or 10-2 games. It's the importance of experience in close ballgames.''
Tracy will hand the ball to Alex White (2-8, 5.31), who is winless in 12 starts since June 3. White allowed one unearned run and two hits while issuing four walks over four innings of a 1-0 loss at Atlanta on Wednesday.
"My four-seam (fastball) is actually the one I had trouble commanding,'' White said. "But I had good stuff, got some guys out and kept us in the game.''
The right-hander is 0-2 with a 7.90 ERA in three starts against the Giants. He surrendered three runs and seven hits in four innings Aug. 12 at AT&T Park, his lone outing in this season's series.