Craig Driver is a second-year coach on the Phillies’ big-league staff and part of their cadre of catching instructors.

His expertise is receiving, a broad term that encompasses everything from a catcher’s stance and placement of the mitt to pitch framing and throwing mechanics. He has devoted years to studying video and conducting research to formulate a model for the best techniques behind the plate.

But after only a few days with J.T. Realmuto, Driver realized there wasn’t anything he could teach the Phillies catcher that would make him better at throwing out baserunners.

“We actually had a conversation early in spring training after we had watched him do some drills and throw to bases,” Driver recalled the other day. “And we kind of said, ‘Hey, if we start telling you stuff about throwing, remind us of this conversation and tell us to stop. Because what you do right now is really good, and if we just let you play the game and use your natural ability and your feel for the game, you’re going to throw out a ton of guys.’ ”

It comes as no surprise then, especially to Driver, that Realmuto has thrown out 35 attempted base stealers, almost twice as many as any other catcher in the majors. It’s the most by a Phillies catcher since Mike Lieberthal cut down 40 in 1997, according to Fangraphs.

In the last 10 seasons, there have been 17 instances of a catcher throwing out at least 35 base stealers. Only six catchers have nabbed 40.

But it’s more than just the volume of runners that are being caught by Realmuto. It’s the percentage. He has snuffed out 46.7 percent of steal attempts, which is leading the majors.

According to Baseball Prospectus, Realmuto has saved 3.8 runs with his arm. James McCann of the Chicago White Sox and the Cleveland Indians’ Roberto Perez are tied for second with 1.2 runs saved.

More context: St. Louis Cardinals catcher Yadier Molina — a nine-time Gold Glove Award winner — hasn’t topped a 45 percent caught-stealing rate since 2014 and has a career mark of 40.6. Jorge Alfaro, the promising catcher whom the Phillies dealt to the Miami Marlins in the February trade for Realmuto, has caught 15 of 40 runners, a 38 percent success rate.

Not bad. Just not Realmuto.

"I think we all felt like we had the most athletic catcher in baseball last year in Alfaro, and we probably acquired the only guy that's more athletic than him," Driver said. "That's been great for us and something that's made our lives a heck of a lot easier."

So, beyond his obviously strong and accurate arm, what is it about Realmuto's technique behind the plate that makes him so successful?

Driver points to how quickly Realmuto transfers the ball from his mitt to his hand. It happens in the blink of an eye, with a fluid motion that resembles a middle infielder turning a double play.

It’s hardly a coincidence that Realmuto was primarily a shortstop at Carl Albert High in Midwest City, Okla., at least when he wasn’t quarterbacking the school’s football team. He had caught fewer than a handful of games when the Marlins selected him in the third round of the 2010 draft and turned him into a catcher in the minor leagues.

As a shortstop in high school, J.T. Realmuto developed the quick release that has enabled him to successfully throw out base stealers from behind the plate.
YONG KIM / Staff Photographer
As a shortstop in high school, J.T. Realmuto developed the quick release that has enabled him to successfully throw out base stealers from behind the plate.

Back then, there were plenty of rough edges. But Realmuto learned his technique in the minors, then refined it in his first few big-league seasons.

He threw out only 27.1 percent of base stealers as a rookie in 2015, but he improved to 35.4 percent in 2016. He has been better than the league average since his rookie year, although he hadn’t thrown out more than 28 runners in a season until this year.

Rob Leary was the Marlins’ bench coach and catching instructor when Realmuto made his big-league debut in 2014. In watching him then and now, Leary believes that Realmuto’s skills as an infielder helped him behind the plate.

“The things which make him so good are his blend of athleticism, quickness, arm strength, and accuracy,” said Leary, now a pro scout for the Arizona Diamondbacks. “Most guys have one or two of those skills, but he possesses each. No doubt his athleticism goes back to his younger days as a shortstop and third baseman and multi-sport star.”

It makes sense to Driver, who has seen other converted infielders be successful at throwing out runners from behind the plate. He cited the Cincinnati Reds’ Tucker Barnhart, a Gold Glove catcher last season who didn’t catch until high school. Boston Red Sox catcher Christian Vazquez, who has a 41 percent caught-stealing rate for his career, was once an infielder.

Both catchers who caught the final out of a World Series for the Phillies played the infield before they went behind the plate. Bob Boone was a third baseman in college at Stanford, and Carlos Ruiz was a squat second baseman until the Phillies signed him out of Panama.

“I think you find with a lot of converted guys, they tend to transfer the ball pretty well,” said Driver, who coached at Yale before joining the Phillies last year. “That’s a big part of playing the infield. It’s a lot of catch-and-redirect, and in reality, all of those throws from home plate to second, or home to third, are all different iterations of double-play turns and things of that nature.”

There are other factors, too. Driver noted that several Phillies pitchers have gotten better at both holding runners and delivering the ball to home plate faster to give the catcher a better chance to make an on-time throw. He also credited coach Bobby Dickerson with drilling the infielders to make better tags on throws from the catcher.

But there’s no denying that Realmuto’s talent is the biggest reason the Phillies have been more effective in controlling the running game. Driver has worked to help Realmuto improve in several areas, including framing pitches. When it comes to throwing out runners, though, it can’t get much better.

“I rarely do any technique-based instruction on throwing with J.T.,” Driver said. “It’s mostly, ‘Hey, I’m going to stay out of your way because I know you do this really naturally and I don’t want to make this any more robotic than it needs to be.’

"But we do look at every pitch that he catches and assess anything that needs to be done. There’s been some small tweaks along the way. But when you have a guy that’s already been an All-Star that you acquire, you pretty much let him go.”

And if you’re the Phillies, you marvel at how good he is.