"We've been pitching well," Wacha said. "[Luke] Weaver's been doing an outstanding job, not skipping a beat. He's performing great out there and giving us a great chance to win ballgames. Just try to feed off one another and keep using that momentum going into the next game."
Wacha had some unsightly starts that led to a 2-3 record and 6.04 ERA for the month of August, but he won his final start of that month and his first of September. He allowed four earned runs over 12 innings in those outings.
"I think there's probably just something small missing with his offspeed pitches," Cardinals manager Mike Matheny said. "I haven't seen the changeup probably be as dominant as it has been, which leads to swings and misses with the strikeouts. But [his] fastball looks good.
"I think it's been a huge compliment to him to be able to figure out that curveball and how to use it, when to use it, and then the cutter, too, which makes him not so dependent on that changeup. That's kind of been the secret -- fastball down and a good changeup -- but now he's got the ability to throw the cutter and the curveball, too, so he's not as predictable."
Opposing Wacha will be Pirates right-hander Ivan Nova, whose last turn in the rotation was skipped.
"It was not what I was looking for," Nova said on Saturday. "Obviously, they decided to do it for a reason, and I'm just looking forward to tomorrow. You don't want to skip a start, you want to pitch every five days. Things went like that, and I've got to accept it."
Nova went 2-3 with a 6.28 ERA in five July starts and then 1-4 with a 5.63 ERA in six starts in August.
Three things to know about this game
• Pirates outfielder Andrew McCutchen is hitting .353 with two doubles, one triple, one homer and three RBIs in his career against Wacha.
• Outfielder Dexter Fowler is the only Cardinals player with more than six at-bats against Nova. He is hitting .300 with one RBI.
• Cardinals second baseman Kolten Wong returned to the lineup on Saturday after missing five games with a tight back. Wong batted .347 for the month of August, the ninth-best mark among National League hitters.
Nate Latsch is a contributor to MLB.com based in St. Louis.
This story was not subject to the approval of Major League Baseball or its clubs.