ST. LOUIS -- Prepared to start Adam Wainwright on Wednesday, the Cardinals, knowing that they have clinched the second Wild Card spot in the National League, will instead send rookie Shelby Miller to the mound to face the Reds for his first Major League start.

The Giants' 4-3 win over the Dodgers late Tuesday provided the Cardinals with the flexibility to make the swap. With a playoff spot sealed, St. Louis has decided to hold back Wainwright, presumably so he can pitch Game 1 of the National League Division Series, should the Redbirds move past the Braves in Friday's Wild Card Game.

Wainwright would also be available for that game Friday, if the Cardinals want to put him on the Wild Card Game roster as protection in case anything happens to Kyle Lohse.

Wainwright will lose out on the chance to pitch 200 regular-season innings by having his start skipped on Wednesday. He's thrown 198 2/3 this year, his first one back since undergoing Tommy John surgery.

As for Miller, Wednesday's start will be his first since Aug. 31, when he made his final Triple-A start of the season. He was then called to St. Louis as one of the organization's September callups and has since been pitching out of the 'pen.

Miller, who entered 2012 ranked by MLB.com as the organization's top prospect, has allowed two earned runs on eight hits in 7 2/3 innings out of the Cardinals' bullpen.

Miller's last multi-inning appearance came on Sept. 10, meaning that St. Louis will have to line up several pitchers behind him to cover all nine innings of the season's final game.

Matheny recognizes importance of celebrating

ST. LOUIS -- Over the past week, differing opinions emerged from the Cardinals' clubhouse about whether or not clinching a spot in the Wild Card game warranted a champagne-popping, raucous celebration -- much like the one the Braves partook in last week, when they sealed their place in the postseason.

Some St. Louis players thought it better to wait until after the Wild Card game. Others felt it is still beneficial to recognize getting into the postseason, even if it only meant one guaranteed playoff game.

It appears as if the Cardinals would proceed with the latter mindset -- though the celebration would be subdued.

The Cardinals had about 15 cases of champagne and beer ready to pour on Monday night, though the beverages stayed on ice since Los Angeles pulled out a win. Still, Matheny praised players for willingly sticking around for several hours after the completion of their own game to watch the West Coast outcome as a group.

"What we were trying to do was the right thing," Matheny said. "[We were trying to do] the right thing for ourselves and not taking this for granted -- for the league and making sure we give them the impression, which is true, of how grateful we are for the opportunity, and same for our fans. Not look smug like it's not that big of a deal. It's a huge deal. If it happens when a game out in California ends, so be it. It's been a long haul, and there's a lot to be proud of."

Matheny also made a point to remind his players as they left the stadium shortly after midnight that they had won on Monday, "even though it didn't feel like it after watching that game," he said.

The Cardinals can eliminate the need for a repeat watch party on Tuesday by winning their game against the Reds. A victory over Cincinnati would leave the Dodgers with no chance to catch up.

Worth noting

• Adam Wainwright remains on schedule to pitch Wednesday if the Cardinals do not clinch the second National League Wild Card on Tuesday. Wainwright likely won't make the start if St. Louis has nothing riding on the outcome of the season's final game. That would allow the Cardinals the flexibility to start Wainwright in the Wild Card game or in Game 1 of the Division Series.

• If the Cardinals advance to the postseason, they're likely to keep only one left-handed reliever on the roster for any series past the Wild Card game. Though Marc Rzepczynski is the only lefty who has been on the 25-man roster all year, Sam Freeman has been getting more pivotal assignments out of the 'pen lately.

Because the Cardinals are comfortable in letting Edward Mujica, Mitchell Boggs and Jason Motte face batters from both sides of the plate, St. Louis has not had much of a need for a late-inning lefty specialist since Mujica was acquired at the Trade Deadline.

• With his 78th appearance on Monday, Boggs tied Jason Motte (2011) for the most appearances by a right-handed reliever in franchise history. Boggs' 78 appearances rank fourth-most in the National League. He also leads the league in holds, with 34.