ST. LOUIS (AP) – The St. Louis Cardinals are about to find out if their late-season pitching swoon was just a collective exhale after months of dominance, or a reason for concern.

St. Louis, coming off its second straight 100-victory season, opens the postseason today in a best-of-five division series against the San Diego Padres, who were only 82-80. But the Cardinals’ recent pitching struggles could be the equalizer.

“I know the last couple of weeks we hadn’t pitched as well as we’re capable of pitching,” pitching coach Dave Duncan said. “I’d like to attribute that to maybe that edge that you lose when you know you don’t have to win the game.”

The Cardinals trot out a formidable group: Chris Carpenter (21-5), Mark Mulder (16-8) and Matt Morris (14-10) in the first three games, with Jeff Suppan (16-10) and Jason Marquis (13-14) in reserve. Because of two days off in the series, Carpenter could go again if a Game 4 is needed on Sunday, just as the Padres likely would return with their ace and Game 1 starter Jake Peavy (13-7).

But all of St. Louis’ starters except for Suppan have bad outings to live down or shake off, contributing to a 6-8 finish after the Cardinals became the first team to clinch on Sept. 15. The Cardinals recovered with a three-game sweep of Cincinnati to close the season despite poor starts from Mulder, Marquis and Morris.

In Carpenter’s case, there’s a string of mediocre performances. Heading into September, the right-hander was the likely favorite for the NL Cy Young Award, but not anymore. He has a sorry 9.14 ERA in his last four appearances, hiking his overall ERA 62 points to 2.83.

Carpenter threw 241 2-3 innings, by far a career high, but insists that disinterest – not fatigue – is responsible for his fade.

“We clinched and there was nothing on the line anymore,” Carpenter said. “Everybody was talking about who we’re going to play and what day we’re going to play and all that kind of stuff and you lose that little tiny edge.

“I think everybody is ready to go and we’re excited about this series.”

Mulder has lasted only 5 2-3 innings in his last two starts and surrendered 10 runs, seven earned. Morris began the year 10-1 but was 0-6 in his last seven starts and his ERA was 5.32 after the All-Star break.

Morris is the longest tenured Cardinal, having been with the team since 1997, and he started the final regular-season game at Busch Stadium on Sunday. In three innings, Morris gave up five home runs, and the Reds hit three consecutive homers to start his final inning.

“It wasn’t the start I would have pictured, the storybook ending type of deal,” Morris said. “But it’s time to move on. The regular season is over.”

Peavy, on the other hand, allowed three earned runs in 15 2-3 innings in his last two starts. He’ll be followed by Pedro Astacio (4-2) and Woody Williams (9-12) in Games 2 and 3, with Adam Eaton (11-5) available for a Game 5 if needed.

Manager Bruce Bochy downplays Peavy’s lack of postseason experience. This will be the playoff debut for the 24-year-old right-hander, but Bochy notes his first career start was against the Yankees and he pitched in the All-Star game this year.

“This kid’s makeup is off the charts,” Bochy said. “We’re excited to have Jake all ready to go.”

Peavy knows this is the biggest test yet. The Cardinals are without Scott Rolen, who had season-ending shoulder surgery in August, but still have one of the most dangerous lineups in the game led by Albert Pujols and fortified by a healthy Larry Walker, who had a fourth cortisone shot for a herniated disc in his neck just in time for the playoffs.

“There are some good lineups, but this is as good as it gets,” Peavy said.

Still, Peavy seemed pretty confident about his ability, and the fact the Padres belong despite their so-so record.

“I don’t think not being in the playoffs is going to affect me throwing a fastball down and away,” he said. “The bottom line is we’re here, we’re excited to be here, and we expect to win.”

AP-ES-10-03-05 1843EDT