Updated

The St. Louis Cardinals try to pad their lead atop the National League Central when they shoot for a series win over the Colorado Rockies Thursday in the finale of a four-game set at Coors Field.

The Cardinals posted a 4-3 win over the Rockies on Wednesday and grabbed a two-game edge on the Pittsburgh Pirates in the division. The Pirates have lost three in a row, including a recent 3-2 setback to the San Diego Padres.

St. Louis starter Adam Wainwright yielded three runs on 10 hits while striking out eight batters in 7 2/3 innings for the win on Wednesday and went 3-for-3 at the plate with two RBI.

Yadier Molina and Matt Carpenter each had a pair of hits with an RBI in the triumph, the Cardinals' ninth in their last 12 outings. Not only do the Cardinals have to worry about the Pirates on their tails, but the Cincinnati Reds sit 2 1/2 games off the pace.

"It's hard to ignore," Cardinals manager Mike Matheny said of the pennant race. "We know what's going on in the rest of the league."

The magic number for St. Louis to clinch the NL Central is nine and the club will visit the Milwaukee Brewers this weekend. The Cardinals, who posted an 11-4 win on Tuesday, are a season-best 26 games over .500 and hope to capture home-field advantage in the NL soon.

Cardinals rookie Michael Wacha gets the ball Thursday and is 3-1 with a 2.81 earned run average in 13 games (7 starts). Wacha lost for the first time in his career in Saturday's 4-1 defeat at the hands of the Seattle Mariners and allowed two runs in five innings.

Wacha, a right-hander, has never faced the Rockies.

Colorado will try to split this set with the Cardinals and has lost nine of its last 12 games. Tyler Chatwood was tagged for four runs on eight hits over six innings in the loss for the Rockies, who won the opener of this set on Monday and fell to 1-2 on a nine-game homestand.

"Those are the type of games you want to be in ... it's a playoff team and he's one of the best pitchers in the league," Chatwood said. "That's the competition you want to go out there against."

Troy Tulowitzki had two hits and two RBI in the loss. Rockies outfielder Michael Cuddyer left the game with an elbow and wrist injury after diving to make a catch in the sixth inning. He is considered day-to-day and leads the NL in batting with a .331 average.

"The main thing is my wrist ... I caught it (and twisted it)," Cuddyer said on the club's website. "Then I don't know if I hit a sprinkler head or what with this forearm. I was running off the field and it looked like a golf ball, like you could tee it up right off my arm. Grass shouldn't do that. I don't know what I hit out there.

"I came out because of my wrist. I mean, the forearm is tight and swollen. I guess you could say I came out for both. But the wrist is the one that bothers me more."

Veteran starting pitcher Roy Oswalt hopes to crack the win column when he toes the rubber Thursday for the Rockies. Oswalt is 0-6 with a 7.71 ERA in six games (5 starts) with the club and pitched in Saturday's 9-2 loss at Arizona, allowing two runs and seven hits in 4 2/3 innings.

Oswalt has plenty of experience against the Cardinals from his days with the Houston Astros and is 10-9 with a 3.19 ERA in 31 career games (30 starts).

Colorado lost two of three games at St. Louis from May 10-12 and went 2-5 in last season's series with the Cardinals.