Carpenter lasted just three innings in Sunday's Game 2 of the National League Division Series, allowing four runs on five hits and three walks. It was the first time he allowed three runs in the first inning since the 2006 playoffs against the Mets.
But manager Tony La Russa had no regrets after the Cardinals' fitting come-from-behind 5-4 win, and Carpenter said pitching on short rest played no part in his shortest outing since July of last year.
"I really physically felt great," Carpenter said. "My shoulder, elbow, body -- everything felt good. But mechanically, I wasn't as sharp as I would have liked, and mentally, I wasn't as sharp as I would have liked. Mentally in that first, I wasn't where I needed to be. I wasn't locating, and that was a lack of concentration."
Carpenter allowed the first four batters to reach base, serving up a leadoff double to Jimmy Rollins before two walks and a Ryan Howard single gave the Phillies a quick 2-0 lead.
"Suddenly, I'm facing Ryan Howard, bases loaded and nobody out," he said. "That's now how you draw it up in the pitchers' meeting."
Carpenter got Shane Victorino to fly out, then Raul Ibanez singled home another run before Philadelphia's big inning finally ended when Placido Polanco grounded into a double play. But the damage was done against Carpenter, who needed 30 pitches to get through the first and 26 more to get through the second, when the Phils added a fourth run.
Carpenter put together a much-needed eight-pitch inning in the third, getting three straight outs, but that was all La Russa would see from his ace.
With the Cards threatening to tie the game in the top of the fourth inning, Carpenter was replaced by pinch-hitter Nick Punto, who struck out swinging with two runners in scoring position and only one out.
Entering 2011, 21 pitchers have started on short rest in the postseason since 2005, and only five have won. The cumulative ERA of the group was 5.83 before Carpenter's start.
"To make a decision like that, [pitching coach Dave Duncan] and I gave it a lot of thought," La Russa said afterward. "We've been around a long time, we know the risks. But you know, you have to prove to your team that you're going to take your best shot. If we would have won Game 1, maybe it would have changed it. But you can't leave here with the caliber of [Cliff] Lee out there and the club not put Carp out there.
"We were going to watch him. And we were not going to let him get to a place where he was real labored. ... But at one point, when we just tied [the game], I said, 'Dave, I feel good, he's not going to be the losing pitcher.' We care that much about him."
Carpenter's velocity was a tad below its average for the year. While his cutter has averaged 88.6 mph this season, it averaged 86.9 on Sunday. His curveball was 1.5 mph slower than normal, and his fastball was one mph behind.
"I did the best I could," said Carpenter. "Did I pitch great? No. But we won, and that's all that matters."
Jason Mastrodonato is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.