Houston — The St. Louis Cardinals tried to be optimistic Tuesday night after a second straight shutout left them with an 11-15 record in August and seven games behind first-place Cincinnati in the NL Central.

"It's a good thing tomorrow starts a new month," Jon Jay said. "It's September, so hopefully we can get on a roll. We just hope that this was just one bad month. Hopefully we can all stay positive and keep looking at the big picture. Tomorrow is a fresh start."

Wandy Rodriguez pitched seven innings and three relievers completed the three-hitter as the Astros again beat the slumping Cardinals 3-0.

Hunter Pence drove in two runs in Houston's three-run fourth inning.

The Cardinals were also shut out Monday when J.A. Happ threw a two-hitter in a 3-0 win. They have dropped four straight and seven of eight.

"The answer is, we're trying," St. Louis manager Tony La Russa said. "The guys are working on different things, the coaches are working on different things. It's not for lack of trying or lack of adjusting. It's not lack of concentration, we're just not making it work."

Tim Byrdak replaced Rodriguez (11-12) for the eighth, but was chased when he walked his first batter. Wilton Lopez finished the inning.

Brandon Lyon gave up a double to Matt Holliday in the ninth and walked Skip Schumaker with two outs, but pinch-hitter Randy Winn struck out to end the game as Lyon earned his 10th save.

Cardinals starter Chris Carpenter (14-5) yielded six hits and three runs with two walks in seven innings.

"Right now it just seems like it's everything," Carpenter said. "Right now, we pitch well and we're not hitting. We don't pitch well, we score a bunch of runs. It just seems that it is a little bit of everything, and it seems like we just can't do anything right."

Pence's two-run triple that landed just behind Colby Rasmus in center field made it 2-0 in the fourth. Michael Bourn reached to start the inning on an error by Schumaker when he couldn't handle a hard-hit grounder to second. Angel Sanchez followed with a single to set up Pence's hit.

"With a guy like Carpenter on the mound you don't get too many opportunities to have first and second, nobody out," Pence said. "So really I was just trying to get in there and ... get Bourn to third. Fortunately I was able to find a hole."

Chris Johnson's single to right field later in the inning scored Pence and made it 3-0.

Rodriguez had some trouble in the first inning, walking Albert Pujols with two outs before he advanced to second on a wild pitch. The left-hander settled down to retire 10 of the next 11 batters.

Rodriguez walked ex-Astro Pedro Feliz with two outs in the fourth, but the Cardinals didn't get another baserunner until Yadier Molina reached on an error by Johnson at third base to start the seventh. Rodriguez struck out Feliz before Schumaker and Brendan Ryan grounded into forceouts to end the inning.

Houston's starters have a 2.16 ERA in the last 22 games and haven't allowed a run in the last 18 2-3 innings.

"It's becoming a nice habit to come in and say that our pitching did an outstanding job," manager Brad Mills said. "Wandy did well tonight. He's been throwing the ball extremely well for the last 2½, three months, mixing his pitches extremely well and getting ahead of the hitters. He was almost textbook."

Rodriguez struck out five for his 62nd career win to move past Jim Deshaies and into third place in franchise history for wins by a left-handed pitcher.

Jason Castro and Pence were both tagged out at second trying to stretch singles into doubles.

NOTES: Cardinals RHP Jeff Suppan (groin) will come off the disabled list Wednesday and is scheduled to start. It will be his first appearance since July 31. ... The Cardinals expect LHP Dennys Reyes (left elbow) to come off the DL on Wednesday. ... The Astros will recall OF-INF Brian Bogusevic, INF Matt Downs and LHP Wesley Wright from Triple-A Round Rock and RHP Henry Villar from Double-A Corpus to join the team on Wednesday. They will also purchase the contract of C Brian Esposito from Round Rock. ... Houston reliever Matt Lindstrom (back strain) pitched a scoreless inning in his first rehabilitation outing for Corpus Christi. ... INF Jeff Keppinger (toe) has returned to Houston after his rehab assignment and is eligible to come off the DL on Wednesday.