CINCINNATI -- The St. Louis Cardinals are looking for leadership in their effort to climb back into the National League playoff picture. Time is running out.

On Tuesday, the Cardinals welcomed back one of their field generals when veteran right-hander Adam Wainwright was reinstated from the disabled list. Wainwright will be used in relief for the remainder of the season.

"We need his presence and his leadership," Cardinals manager Mike Matheny said. "We get in the middle of this thing, we have to do whatever we can."

St. Louis (78-72) plays the second of three games against the Cincinnati Reds (66-85) on Wednesday night at Great American Ball Park. The Cardinals are 3 1/2 games behind Colorado for the second NL wild-card spot.

Matt Carpenter is another one of the veteran players the Cardinals are counting on down the stretch. He was given a day off for the series opener but is expected back in the lineup Wednesday. Carpenter is 3-for-13 on the current road trip.

"We have a group of guys that have been kind of our go-to guys in big situations, not just to go through it, but talk about what success should look like this time of year," Matheny said. "You want that current success to match up to the message that you're giving."

Right-hander Luke Weaver (6-1, 1.89 ERA) will start for St. Louis on Wednesday. The 24-year-old beat Cincinnati last week, allowing one unearned run on two hits with six strikeouts over six innings of a 5-2 victory at Busch Stadium.

He allowed five runs and four hits in two-thirds of inning in relief against the Reds last season in his only other appearance against them.

Weaver also has a personal six-game winning streak, the longest active streak in the major leagues. It is tied with Wainwright for the longest streak by a Cardinals pitcher this season. Over his past five starts, Weaver is 5-0 with a 1.15 ERA, having walked four and struck out 42.

Cincinnati counters with right-hander Rookie Davis, a 24-year-old rookie who rejoined the rotation after Triple-A Louisville's season ended. Davis was on the Reds' Opening Day roster and is making his first start since returning to the major leagues. He gave up two runs in two innings in a relief outing at St. Louis on Sept. 12.

Davis is 1-2 with a 7.58 ERA in five starts. He has 13 walks in 19 innings as a starter. He spent 14 days on the disabled list in April due to a bruised right forearm.

Cincinnati is hoping to get center fielder Billy Hamilton into a game during this series, if only as a pinch runner. He is on the disabled list with a fractured left thumb but has resumed baseball activity.

"He hasn't done any live hitting yet," Reds manager Bryan Price said. "We could use him as a pinch runner. It's more or a probability than a possibility. I don't think the first time you see him will be as our starting center fielder."

The Reds will be looking to reach the 1,000-win mark against St. Louis during this series. Cincinnati currently has 998 wins over the Cardinals since 1900. At 9-8 this season against them, including 5-3 at Great American Ball Park, the Reds are looking for their first season series win over St. Louis since 2011.

Cincinnati is 3-3-2 against the Cardinals in the past seven completed series of more than one game.