The same couldn't be said for them in their latest performance without Matt Cain.
San Francisco (36-19) owns the best record in baseball, winning eight of nine with the last two coming with Posey sidelined due to tightness in his lower back.
The Giants haven't seemed to miss the 2012 NL MVP this year. They won 6-5 in the opener of this four-game series at St. Louis (29-26) on Thursday before collecting 12 hits in a 9-4 victory the next day.
They're 5-2 without Posey in 2014.
"It's a very deep lineup," said Cardinals ace Adam Wainwright, who was reached for a season-high seven runs in 4 1-3 innings Friday. "When you take a guy like (Buster) Posey out of the lineup and still have a very dangerous squad, you know you have a deep lineup."
Strong performances from the rotation have also been key, as the starters have compiled a 1.93 ERA over the last 10 games - 1.42 during a four-game winning streak. Madison Bumgarner tossed the latest gem Friday, striking out 10 in seven scoreless innings.
"I think we've got a really good team all the way around and we've showed it," Bumgarner said.
San Francisco, though, won't have Cain available for his scheduled start after placing him on the disabled list Friday, retroactive to May 22, with a strained right hamstring.
Manager Bruce Bochy anticipates Cain will make his next start against the New York Mets next Friday.
Before that, he'll again turn to Petit (3-2, 5.08 ERA), who allowed four runs with five strikeouts over five innings in place of Cain in an 8-4 loss to the Chicago Cubs on Monday.
The right-hander is 1-1 with a 7.08 ERA in four spot starts this season, completing six innings once. He's facing the Cardinals for the first time since a road loss with Arizona on July 19, 2009.
Pablo Sandoval has batted .382 with six homers and 19 RBIs in the past 19 games after hitting .171 through the first 34. The third baseman has put together a 10-game hitting streak, during which he's 15 for 36 with five homers and 14 RBIs.
Sandoval and the Giants get their first-ever look at Michael Wacha (3-3, 2.67), who has gone 6-0 with a 1.77 ERA over his last nine home starts - two of those coming during the NL championship series.
The right-hander hasn't allowed more than three runs in any of his 11 starts this year. He yielded three runs and four hits in seven innings of a 6-4, 12-inning loss to the New York Yankees on Monday.
Allen Craig has batted .400 with 12 RBIs over the past 10 games. That includes two doubles, one homer and three RBIs in this series, giving him a .388 average with five homers and 15 RBIs in 13 home meetings with the Giants.
Cardinals top prospect Oscar Taveras is expected to be available for his major league debut after being called up from Triple-A Memphis on Friday. The 21-year-old outfielder is replacing Matt Adams, who was put on the DL with a left calf strain.
Taveras was batting .325 with seven homers and 40 RBIs in 49 games with Memphis.
"I would expect him to come up here and hit," outfielder Randal Grichuk told the team's official website. "I saw him down there for a couple months and his ability to barrel up balls is through the roof. I expect him to come up and do very well."