St. Louis ? The pitching staff that wasn’t supposed to be good enough to contend, more than the All Star-studded lineup, has the St. Louis Cardinals on top of the National League.

“Our starting five didn’t get a lot of recognition at the start of the year,” center fielder Jim Edmonds said. “But they’re the reason we’re here.”

The Cardinals are 20 games above .500 and have a six-game lead in the Central Division entering a weekend series with the Cubs, one of the two teams they were supposed to be chasing in vain in the NL Central. So far they’ve made the leap from a disappointing third-place finish last year without making any major moves.

The rotation of Matt Morris, Woody Williams, Chris Carpenter, Jason Marquis and Jeff Suppan combined for a measly 42 victories last season. Popular wisdom had the Cardinals battling for third again.

Instead, the rotation leads the major leagues with 53 quality starts, three more than the Cubs. Just past the halfway mark, and with slow starts from both Morris and Williams, the starting five already has produced 39 victories.

The two biggest surprises have been Carpenter, out 20 months following shoulder surgery, and Marquis, who spent most of last year in the Atlanta Braves’ minor league system. Last year they combined for zero wins, and this year they already have 17.

Carpenter has become the de facto ace, a power pitcher who has often dominated and routinely gets deep into games. Before he was injured in 2002, Carpenter was becoming the staff leader with the Blue Jays and this is developing into the breakout year he expected to have three seasons ago.

“I was just on the verge after 2001,” he said. “In 2001, I was just learning to pitch a little bit, and before that I was just a heaver.”

Marquis, 8-4 with a 4.10 ERA, also has resurrected his career after falling out of favor with the Braves. He had a 5.53 ERA with Atlanta last year but the Cardinals saw enough promise to acquire him along with reliever Ray King in a deal that sent J.D. Drew and Eli Marrero to the Braves.

When he beat the Mariners last Saturday, Marquis matched his career high for victories set in 2002.

“Good,” pitching coach Dave Duncan said. “He’s going to get a bunch more, too.”

Jeff Suppan was a low-key free agent acquisition for $6 million over two years and he has a staff-low 3.25 ERA to go with a 7-5 record.

“It’s not just eating innings,” manager Tony La Russa said. “It’s quality pitching as well.”

The guys at the top of the rotation have struggled the most. Morris’ velocity is down from previous seasons and if he misses his location, it’s trouble with an NL-high 24 homers allowed. He’s tied for the staff lead in victories and is 9-6, but with a staff-high 4.33 ERA.

Williams, an 18-game winner last year, stumbled to a 1-5 start after pitching only five innings in spring training due to shoulder tendinitis. He’s finally found his stride, going 3-0 with a 1.89 ERA in his last five starts.

Middle relief also has been strong, keeping games tidy for closer Jason Isringhausen. King has been stingy enough (1.16 ERA) that he was disappointed at not getting All-Star consideration, and the bullpen was second in the major leagues with a 3.28 ERA.

What’s generally considered the NL’s best everyday lineup ties it all together. Third baseman Scott Rolen, first baseman Albert Pujols and shortstop Edgar Renteria give the NL three infield starters from the same team for the first time since 1982.

“You see them do something amazing every day,” catcher Mike Matheny said. “There’s hardly a day that goes by that you don’t see Scotty make a play that you shake your head about, or Edgar do the same thing, and all these guys at the plate.”

Rolen, the leading vote-getter in the NL, is enjoying a career year with a major league-leading 80 RBIs and a .347 average along with Gold Glove defense despite being bothered by joint irritation in his left knee for the last month.

Renteria has been picking it up offensively after struggling at the plate earlier in the year. He hit the go-ahead homer in Tuesday’s victory over the Reds.

“Sometimes you start slow, sometimes you start fast,” La Russa said. “He goes about it the right way.”