A version of this story originally ran in December 2020.

It sounds like some sort of baseball folk tale, some ridiculous bedtime story your grandfather might tell you when you were a little kid and believed everything you heard.

A young boy, growing up tough in the southern Appalachian corner of Tannersville, Va., breaks his right arm -- his natural arm -- twice, before the age of 7. He somehow learns how to throw with his left hand, eventually reaches speeds of 100 mph, goes to the Major Leagues and becomes one of the most dominant pitchers ever.

Only this story's even better because, well, it's real.

"Yeah, I mean, I'm still pretty much right-handed," Billy Wagner tells me over the phone from his home in Virginia. "I'm right-footed, as a kicker I punt right. I cut my food with my right hand. I'd probably poke my eye out with my left hand with a fork."

Billy Wagner's right-handed to left-handed transformation story has been told before, but definitely not as often as it should. And with his name once again on the Hall of Fame ballot (he has gained significant ground over the past two voting cycles), we called him up to see if there were any details he could fill in. We also talked to a New York City kinesiologist to see if anybody could do what Wagner did, or if, you know, he's just a super freak athlete and we're all mere mortals.

• Roundtable: Is Wagner a Hall of Famer?

Wagner was always a sports-loving kid growing up -- mostly football and baseball -- so when he broke his arm playing football with a neighbor and once again while climbing some monkey bars, he didn't want to miss out on any games or activities with his friends. He had this other arm just hanging there, why not use it?

"I think as a kid, you just have that natural instinct that you're gonna do stuff. No matter what," Wagner says. "Kids are so resilient and I wanted to play. I wanted to do things. I think that natural competitiveness of, 'I'm gonna play,' took over."

"Yes, it's called neuroplasticity: the ability of our body to adapt to whatever we put on it," Dr. Eugene Charles, who pretty much wrote the book on this subject, tells me over the phone. "I believe we have this ability all throughout our lives. But the general consensus is that it's even more powerful [when we're younger]. Science says we have more pliability and neuroplasticity then ... and also less self-imposed inhibitions."

So, Wagner, unknowingly, took this newfound neuroplasticity and built on it. The middle-schooler began throwing anything he could find with his left hand -- baseballs, footballs or even just rocks. Constant practice is also a key to changing dynamics in the brain.

"Yeah, by him just making a concerted effort to go with his left hand, you can re-establish neural pathways," Charles says. "There's the old nature vs. nurture. Nature might be the said foundation but, you know, nurture is really what develops who you are and what you can do."

All of a sudden, as Wagner's right arm was still healing, he found he was throwing harder and harder with his left. That arm became his good arm. He was breaking aluminum siding off the side of his house and striking out batters older and bigger than him in Little League.

"My dad always tells this story of how when I faced the big kids, I had no problem," Wagner remembers. "It was when I faced the little kids that I couldn't throw a strike. I didn't want to hit them."

He clocked his fastball in the low-80s in high school, striking out an absurd 116 batters in 46 innings (while also hitting .451 at the plate). He enrolled at Virginia's Ferrum College to play Division III football, but coaches encouraged him to stick with baseball and his pitching career took off.

"That first year, I gained 40 pounds, I grew 2 or 3 inches," the 5-foot-10 Wagner says. "A substantial growth spurt for me. I went from 78-82 mph to 92-95 mph my freshman year."

The born-again lefty struck out a laughable (and still NCAA record) 19.1 batters per nine innings during one year in college. He struck out 19 during a no-hitter and finished a three-year career with a 17-3 record and 1.63 ERA. He was inducted into the National College Baseball Hall of Fame in 2019.

In the 1993 MLB Draft, the Astros took him with their first pick. He made his debut two years later, struck out an Astros relief-record 106 batters in '97 and made his first of seven All-Star teams in '98. His "weaker" arm was now topping out at 100 mph. Future teammate Chipper Jones was scared to get in the box against him. Famous lefty fireballer and Houston teammate Randy Johnson said, "He's a foot shorter than me, and throws harder than I do."

But even with all the success with his left arm, was he ever curious what he could do with his right? Did he ever test it out?

"No, no, no, no," Wagner laughs. "I don't think it would be anywhere near [my left]. I can't even put a number on it. I don't think it would be anywhere close to that."

Wagner did have a funny story from his time in Philadelphia involving visiting pitcher Kenny Rogers. Rogers, a lefty, challenged Wagner to a throwing contest using their opposite hands. Rogers, of course, had no idea that Wagner was a natural righty.

"We're standing by the batting cages and I say, 'OK let's see,'" Wagner recalls. "[Rogers] picks up a baseball and he throws it down the foul line and one-hops it to the seats. I pick up a ball and I throw it right into the seats. Cages, down the third-base line, into foul territory the furthest part."

Wagner retired his golden left moneymaker in 2010 at the age of 38, after putting together one of his greatest seasons: 37 saves, 1.43 ERA, 13.5 K's per nine innings. He struck out the last four batters he faced. He could've probably played a couple more years, but his desires shifted to spending more time with his kids and coaching baseball, which he still does today at Virginia's Miller High School.

"Oh yeah, I throw BP all the time," Wagner says. "Father Time's caught up with me, but I still get on the mound and compete against them."

He said he got it up to 90 mph a couple years ago and that his control is much better now. He also mentioned that he can throw some solid BP with his right arm.

So, what's the answer? Do we all have the ability to do what Wagner did? Dr. Charles thinks so ... with a caveat.

"Everyone can do it," Charles says. "But where he deserves all the credit, and a Hall of Fame nod, is that he had the discipline and determination to do it. That's the caveat: You have to have his discipline and persistence. That's kind of the X-factor."

So, yes, anybody has the capacity to do it. But not everyone will do it, be able to throw faster than a hurricane, become an elite Major League closer and be knocking on the door of Cooperstown.

Everyone can do it, but not everyone can be Billy Wagner.