Back then, he was a rookie just trying to establish himself. Now, Carpenter has become a key man out of the Atlanta bullpen, leading the team with 19 appearances this season.
"When I first came up with the Astros, it was just a matter of getting your feet wet and I was still learning how to pitch," Carpenter said. "Learning how to try and work counts and all that type of stuff. I've continued to learn that and just feel a little more confident in my stuff and feel a little more relaxed out there."
Carpenter picked up one of his two wins this season when the Cardinals visited Atlanta on May 6. More recently, he picked up his second save of the season with a perfect ninth inning against the Cubs on Sunday.
Carpenter still remembers playing with current Cardinals such as Yadier Molina, Allen Craig and Jon Jay in the Minors.
"It's fun to get a chance to come back here and reconnect with all the guys, but it's just a matter of going out there and we're not friends when they step into the batter's box," Carpenter said. "It's all about trying to get them out and trying to give our team a chance to win."
Joe Harris is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.