ATLANTA — The evolution of catcher framing metrics has changed how certain attributes are evaluated behind the plate.

Major League Baseball’s introduction of the Automated Ball-Strike (ABS) challenge system this year creates another layer to a catcher’s defensive skills — if accuracy at getting calls overturned is truly a skill.

While the sample size remains small 41 games into the season, Chicago Cubs catcher Carson Kelly has been among the best at using the ABS system to turn balls into strikes for his pitchers.

“Knowing he’s so good at it makes me, when I’m out there, it’s literally not even a thought in my head,” right-hander Jameson Taillon told the Tribune on Tuesday. “Like, I don’t even worry one bit about it. You could call it skill. But I think for him, the speed of the game, he’s not emotional when he does it, so he’s thinking through it.”

Entering Tuesday’s series opener in Atlanta, Kelly was 18-for-20 in ABS challenges, a 90% success rate that tops all catchers (minimum 10 challenges). He has gained eight strikeouts with successful challenges, tied with the Athletics’ Shea Langeliers for second in the majors. Kelly also has eliminated three walks, good for fifth.

“A lot of it’s situation dependent,” Kelly said over the weekend in Texas. “It’s knowing when to use them and how sure you are of it being a strike.

“There was one (against the Rangers), I set it up away and there’s a ball up and in that ended up clipping that was a strike. But I wasn’t 100% sure, or 90% sure, that I thought it was a strike. There’s a certainty level of trusting your eyes and just understanding the situation.”

Manager Craig Counsell credits Kelly’s understanding of game situations in deploying the team’s challenges.

“I don’t know how you practice being good at that,” Counsell said last week at Wrigley Field. “Carson was very conservative in spring training. But to his credit, he was just feeling the system out as much as anything. We get feedback every single day, obviously, so you know the ones he’s missed.

“He’s just done a good job of taking in all the feedback that you get on a daily basis when you catch and having a good feel for it. It’s still, for me, too early to tell you if we can assign skill to this. But Carson’s off to a ‘hot start.’”

As a team, Cubs catchers have combined for a 71% success rate on challenges, behind only the Detroit Tigers (83%).

Sometimes impactful challenges might not go in the Cubs’ favor or are unnoticed. Taillon pointed to two challenges by Miguel Amaya during his May 5 start against the Cincinnati Reds that he felt played a key role in his strong outing. He threw the Reds’ Tyler Stephenson a full-count, back-door two-seamer that resulted in a walk. Amaya challenged the call, but it was confirmed to be a ball by about 0.2 inches.

“But I just thought that was such a good pitch to challenge because I had been struggling a little bit that inning, and if he gets us a strike there …” Taillon said. “So I remember thinking that was unsuccessful but thought that was a really smart, good challenge.”

Amaya also challenged a 3-0 pitch to TJ Friedl that reversed a walk; Taillon retired Friedl on the next pitch.

“It seems like a insignificant challenge, but then it got me a leadoff out — that’s a huge deal,” Taillon said. “Both of them are really good. (Kelly is) just so measured with it. It’s really nice to know that he’s in charge of it.”

If there’s any initial takeaway from ABS in the majors, Taillon and Kelly both praised how great MLB umpires are at calling the strike zone. Kelly put it simply: “We’re talking quarter of an inch at 100 miles an hour. They’re really good at their jobs.”

Through the first six-plus weeks of the season, 53% of all challenges, from both catchers/pitchers and hitters, have resulted in overturned calls.

“Umpires are really freaking good at their jobs, to be completely honest,” Taillon said. “If you had put ABS in the game 20 years ago, I think you would be like, umpires are bad, but umpires in recent years, I’ve just noticed the zone getting tighter and more consistent. … The ones that are 0.1 inches, crazy. Honestly, it’s impressive.”

Sullivan reported from Arlington, Texas.