But if Carpenter has shown any ill effects since then, he has hid them well. The right-hander finished off his college career with six victories and a 3.81 ERA in 13 starts spanning 75-plus innings while striking out a team-high 88 batters in 2008.
His success post-surgery is all about determination and hard work, said Kent State head coach Scott Stricklin, who has mentored Carpenter the last four seasons.
"He's overcome a lot of adversity the last few years," notes Stricklin. "He had to go through the (initial) surgery and then the doctor had to go back in and practically redo that surgery. For him to overcome it, I think it says a lot. He's overcome a lot of adversity to get to this point and he's an extremely hard-working young man."
Now Carpenter is on his way to the next level: the professional ranks. He signed a tentative contract to play for the Cubs last week and is scheduled to finalize the deal this week in Mesa, Ariz., at the site of the club's spring training headquarters.
After a solid season with Kent State in 2008, Carpenter is excited as he prepares to embark on this next journey. But it wasn't so long ago that he wasn't quite sure what his future held in store in the wake of surgeries to his throwing arm.
"It was my freshman year and I was a weekend starter," recalls Carpenter. "It was May 8, 2005. I was throwing in a game, threw a fastball and I guessed that something wasn't right with my arm. I threw one more pitch and after that, I knew something was wrong. My arm was burning and I ended up coming out of the game. I went to the doctor after that and he said that I had torn my UCL and that I needed Tommy John."
Carpenter had heard many stories from other pitchers detailing the moment they first realized something was amiss with their arms. But it wasn't until that spring day in 2005 when he threw a 93 mph fastball and felt a pop in his own elbow that made him realize this was the scariest moment he'd ever experienced as a pitcher.
"You hear people talk about it all the time, but it doesn't ever really hit you until it actually happens to you," says Carpenter. "When you can't throw anymore, you're like, ‘Wow. I love baseball (but) I can't throw right now.'
"You kind of ask yourself, ‘What do I do now?' It was really scary."
He recalls a meeting that he had with Stricklin and Kent State associate head coach/pitching coach Mike Birkbeck in 2006 that would inspire him.
"They told me that I could do two things," Carpenter recalls. "I could go one way and feel bad about the situation, or I could try to work harder and come back stronger from it. After that meeting, something clicked in my head and I started trying to get stronger and get in shape. It kind of turned me around. I started eating right. I got into shape and got a lot stronger. I think that helped out. It all clicked when I came back."
Already a hard-thrower before going under the knife, Carpenter touched 96 mph the first time he was clocked with a radar gun (post-surgery) against live hitters in a game against the Louisville Cardinals in 2007. Stricklin, for one, was in awe.
"The first time he really let it go, I was actually catching him myself and we had another pitcher that was coming back from a shoulder (injury)," recalls Stricklin.
"I was very comfortable catching the guy with the shoulder (injury), but I started to get a little uncomfortable catching Chris. We didn't have the radar gun on him, but I knew the velocity was getting up there. When he started facing hitters and we put the radar on him, the first time he faced hitters live, he hit 96 miles per hour. It was one of those things where he worked very hard to get himself in the best shape possible. He did all of his rehab and everything got stronger, and it just kind of came together."
And it hasn't unraveled since.
While pitching uninterruptedly this season, Carpenter's fastball was consistently clocked at 93 to 96 mph. That prompted Chicago Scouting Director Tim Wilken to describe Carpenter's velocity as "plus-plus" at times, and Stricklin said that Carpenter also showcased a hard breaking ball that was 82 to 85 mph at times.
"Last year, his breaking ball was very average, probably a little bit below average and his changeup was very erratic," Stricklin described. "This year, his breaking ball really sharpened up. I think the reason that it did is he had a lot more confidence in his arm. His off-speed (pitch) is much better and he was throwing his breaking ball instead of [babying] it. It's very, very hard, and it's got a 12 to 6 break on it.
"His changeup is a plus pitch. He's able to get left-handers out with it. He's a guy that could go through the Cubs' system very quickly. I think he could be in the major leagues very quickly because of his arm strength. He's got a plus changeup and a plus breaking ball. He's a very hard worker, so I think he can move quickly."
Carpenter says he has set no ETA for himself.
"I don't even know what to expect," he said. "Obviously I want to get to the next level as soon as possible, but it's just something that I'm going to work as hard as I can at. Hopefully I'll produce and people will see that and I'll move up. It's not something where I have a timeline. I know how good I think I am, and hopefully my talent shows that and I'll move my way up."
Being drafted by Chicago is just more icing on the cake for Carpenter. A native of Northwest Ohio that played both baseball and basketball in his prep days at Bryan High School, he grew up a Cubs fan, idolizing Hall of Fame second baseman Ryne Sandberg, now a manager in Chicago's farm system with Class Low-A Peoria.
The idea of playing for his childhood hero appeals to Carpenter.
"It would be an honor to play for him," he says.
More than anything else, though, this Cubs prospect is just happy, period.
"This past year, I've felt as good as I've ever felt in my whole life," he said.