The right-hander, who ranks as the organization's top pitching prospect, is expected to compete for a Major League rotation spot next spring. The first act of his audition, which came because the Cardinals no longer needed to start Adam Wainwright, went swimmingly.
Miller, who had made five Major League relief appearances, found out that he would be tabbed as Wainwright's replacement on Tuesday night, giving the right-hander enough to time to prepare for the outing. It also allowed Miller the chance to pass along news of the assignment to family and friends. His dad, after finishing an overnight shift as a firefighter at 6 a.m. CT, drove up from Texas for the start to be one of Miller's many supporters in the stands.
"Butterflies and anxiety were there," said Miller, who hadn't pitched since Sept. 26. "I was trying to be as normal as possible -- go about the same routine I always have. It turned out well. I couldn't have asked for more."
Though he hadn't made a multiple-inning appearance since Sept. 10, Miller lasted six innings because of tremendous efficiency. He allowed only three baserunners (two walks, one hit batter) through the first five innings and struck out seven during that span.
He admitted that it was about the fourth inning that he first checked the scoreboard for a reminder -- and sure enough, the Reds had yet to dent the hit column.
"The young man had us eating out of his hands," Reds manager Dusty Baker said. "We hope he has a good career but not indicative of what he was doing against us tonight. He threw the ball well."
Miller opened the sixth with two flyouts before Valdez poked a ball over the head of retreating second baseman Ryan Jackson. Miller followed by getting Joey Votto to ground out to end the frame. Miller left with a pitch count of 72. Of those, 52 were strikes.
"I didn't really know how I was going to feel in it, as far my arm since I hadn't start since [Aug. 31 with Triple-A Memphis]," Miller said. "But my arm felt good and I couldn't have really asked for more. I'm just thankful for the opportunity."
The Cardinals' inability to score until the eighth cost Miller the chance to be rewarded with his second Major League victory. He does leave with a keepsake, though, having pocketed the ball he drilled off the left-field wall for a third-inning double. It was the first hit of Miller's career. He later singled in his fifth-inning at-bat.
"It'll definitely help him as he prepares for next season and walks into Spring Training," Matheny said of Miller's starting experience. "He's done a good job up to this point. We've put him in some spots that I don't know if he expected to be in."
Miller's pair of hits was among the five the Cardinals tallied through seven innings. In his first start since no-hitting the Braves, Homer Bailey tossed the first four of those innings for the Reds. A string of relievers followed him, and St. Louis eventually broke through in the eighth.
Shane Robinson nailed reliever Jonathan Broxton on a comebacker and beat out Broxton's throw to second. Lefty Tony Cingrani relieved Broxton and issued a walk to Skip Schumaker. Reds second baseman Henry Rodriguez, who was brought in as part of a double-switch with Cingrani, then couldn't corral a sharp grounder by Matt Carpenter, allowing Robinson to score from second.
That allowed Matheny to use Marc Rzepczynski and then Jason Motte to seal the team's 21st one-run win of the year. Motte earned his 42nd save of the season, tying him with Atlanta's Craig Kimbrel for a National League-high. This also marks the first time in franchise history that one player has collected every team save.
"I told Mike [Matheny] last night that, 'For you to believe in me every single time, whether good or bad. ... it's pretty cool for you to have my back,'" Motte said.
Though Miller monopolized the spotlight on Wednesday, the night didn't completely belong to him. Despite still being bothered by a right knee injury, Lance Berkman was sent in to pinch-hit with two outs in the seventh.
It was Berkman's first plate appearance since Sept. 7 and possibly the last one of a 14-year career. He has noted several times in recent months that he will contemplate retirement this offseason after being plagued by persistent knee issues again this year. Berkman received a standing ovation from the crowd and from his teammates during an elongated introduction.
"It was really nice," said Berkman, who grounded out after tipping his helmet and waving to the crowd. "I didn't know what the crowd would think when I went up there. It was certainly a nice sendoff."
The Cardinals' sendoff into the postseason is a final regular-season record of 88-74. The club won 50 games at home, but goes on the road now to face the Braves in the one-game Wild Card playoff.