CINCINNATI -- The Cincinnati Reds will play a significant role in the pennant races beginning Tuesday night when they host the St. Louis Cardinals to open a three-game series at Great American Ball Park.

The Reds conclude the home portion of their schedule with a three-game series with the Boston Red Sox thisweekend. Both the Cardinals and Red Sox are in contention for division titles and playoff spots, while the Reds are building for next year and beyond.

Reds manager Bryan Price was asked how he will approach developing young players while also putting a competitive lineup on the field out of respect for opponents.

"We'll have a fairly representative lineup the rest of the season," Price said. "That doesn't mean these young guys aren't going to play. That's our responsibility. The priority is the Reds, not the Cardinals, or the Pirates, or the Red Sox. But I do respect the environment we're in and won't unload the bench."

Rookie right-hander Jackson Stephens will make his second career start for the Reds on Tuesday.The Cardinals also will start a rookie, right-hander Jack Flaherty, who will make his third start since being recalled Sept. 1.

Flaherty, 21, has allowed nine earned runs through 13 1/3 innings, but he'll likely have an extended stay in the rotation during the final two weeks of the season to see what he can do. But not without help.

VeteranAdam Wainwright will be reinstated from the disabled list this week and the former rotation ace will moveinto the bullpen. Wainwright hasn't made a relief appearance since 2015. He faced hitters for the first time during a live batting practice session Sunday.

"That was encouraging," Cardinals manager Mike Matheny told reporters following Wainwright's session. "I don't think it's a situation to stretch him at this point. Make sure it looks good, feels good, and that he can rebound."

The Cardinals (77-72) are coming off a crushing three-game sweep by the Cubs at Wrigley Field and desperately need to get back on track in Cincinnati to rekindle their playoff hopes. St. Louis is six games behind Chicago in the National League Central and 4 1/2 games out of the second NL wild-card spot.

The Reds' Stephens, 23, earned his first major league victory in his debut in a 5-3 win over the Chicago Cubs on July 1 at Great American Ball Park. This will be his fifth appearance in three stints this season with Cincinnati. He led Triple-A Louisville's pitching staff in wins, starts, innings pitched and strikeouts.

Cincinnati (66-84) swept the Pittsburgh Pirates over the weekend at Great American Ball Park and is starting to get solid performances from its young starting pitchers.

The Reds will be looking to reach the 1,000-win mark against St. Louis during this series. Cincinnati has 998 wins over the Cardinals since 1900. At 9-7 this season against them, including 5-2 at Great American Ball Park, the Reds are seekingtheir first season series win over St. Louis since 2011. Cincinnati is 3-2-2 against the Cardinals in the last seven completed series of more than one game.