Ludwick hit a two-run homer and a run-scoring double, Wellemeyer pitched three-hit ball into the eighth inning and the Cardinals beat the Florida Marlins 3-0 on Thursday night.
The Cardinals headed for a weekend series in Cincinnati having won three of four from the Marlins, who dropped well off the pace of the Philadelphia Phillies in the NL East. St. Louis moved to within three games of Milwaukee in the NL wild-card race, after the Brewers lost 3-2 at San Diego to snap an eight-game winning streak.
"Winning three of four ... is huge, especially with Milwaukee losing," Wellemeyer said. "We finally get a game on the Brewers."
Wellemeyer (10-4) walked four and struck out three over 7 2/3 innings, his longest outing of the season. He previously had gone seven innings on four occasions.
Wellemeyer retired 13 straight hitters at one point before walking Hanley Ramirez with two out in the eighth. The Marlins went without a hit between Dan Uggla's lead-off single in the second and Luis Gonzalez's two-out single in the eighth.
Ludwick's two-run homer in the seventh opened a 3-0 lead.
Cesar Izturis led off with a single to left before Joe Mather flied out to right. Ludwick then sent Scott Olsen's 1-0 fastball over the wall in left-center for his 30th home run and RBI Nos. 89 and 90.
"It was a good night. I got on top of a pitch finally in that last at-bat," Ludwick said. "It felt good. I got a good pitch to hit and I drove it."
"He's benefited from a productive team and he's taken advantage," St. Louis manager Tony La Russa said.
Olsen (6-8) gave up three runs, 10 hits and struck out six in seven innings. He lost his fourth straight decision over his past five starts, during which Florida has averaged 2.4 runs.
"It's not from lack of (offensive) effort. It's just something some pitchers have to deal with more than others, and apparently that's me," Olsen said of the lack of run support.
Izturis, batting in the ninth spot, led off the third with a single. He then stole second and took third on first baseman Mike Jacobs's throwing error. After Mather flied out to short center, Ludwick lined a double into the left-field corner for a 1-0 lead.
Ludwick entered the game hitting .217 (5 for 23) on the road trip.
The Marlins were shut out for the eighth time this season and third time in the past nine games.
"It's just a funk," Florida manager Fredi Gonzalez said of his team's recent offensive struggles. "We believe in these guys. I believe in these guys."
- Cardinals right-hander Chris Carpenter will miss his scheduled start Friday with a muscle strain in his right shoulder. Brad Thompson (4-2) will start in Carpenter's place at Cincinnati.
- St. Louis RHP Adam Wainwright (finger sprain) will start for Double-A Springfield on Saturday.
- The door to Gonzalez's office remained close for nearly 20 minutes after the game. When it opened, owner Jeffrey Loria, team president David Samson, president of baseball operations Larry Beinfest and general manager Mike Hill walked out. "We were kicking stuff around," Gonzalez said.