This, from someone who had always been known as a defense-first catcher while moving back and forth from the Majors and Minors -- spending far more time in the latter destination -- for five years.
Leon's latest moment to remember was his most emphatic yet. He jumped on a 2-0 pitch by CC Sabathia in the sixth and hit it a long way into the left-field seats.
"It's all about confidence. I'm just trying to get a good pitch to hit. I got 2-0 and was trying to get a good pitch to hit," said Leon. "I wasn't trying to hit a homer. I was just trying to bring one run to the plate, and thank God I hit a homer."
Statcast™ projected the homer landed 412 feet away from home plate, and the score jumped from 2-1 to 5-1 in favor of Boston.
"Well, the dugout erupted," said Red Sox manager John Farrell. "As soon as he squared it up, I don't think there was any doubt where it might land."
There's something particularly rewarding for a team to watch a player like Leon who has paid his dues to the fullest enjoy some success.
"Off the bat, it sounded good, it looked good and I'm glad Sandy hit it," said Red Sox center fielder Jackie Bradley Jr. "And I love seeing it. He's a great person, great ballplayer, great teammate and he's doing a lot to help this team."
The home run was the third of Leon's career. When was the last time he hit a ball with that type of authority?
"I don't remember," Leon said. "Maybe never until today."
In 612 career games in the Minors, Leon was a .238 hitter with a .654 OPS.
In 59 at-bats for the Red Sox this season, he is hitting .458 with a .731 OPS. Granted, the sample size is small but nonetheless impressive.
"It hasn't been any soft .400," Bradley said. "It's been well-struck baseballs from both sides of the plate. It looks like he's taking full advantage of every opportunity."
A backup catcher in previous stints for the Nationals and Red Sox, Leon is now starting three to four times per week.
"It feels good, but it's only like 60 at-bats," Leon said. "I know it's a lot of hits in 60 at-bats, but like I say, I'm trying to keep it simple and help the team."
The approach is working, and even the most storied hitter on the Red Sox has taken notice.
"He's more aggressive," said David Ortiz. "He's not thinking too much. Towards the end of the lineup, he's going to get pitches to hit. He's got to be aggressive, and that's what he's doing."
"It's such a compact swing," said Farrell. "He's playing with a lot of confidence. He's come up in big spots, he's had very good at-bats and worked deep counts. And he's done a very good job of running the game behind the plate."
Leon's improvement offensively started last offseason in winter ball.
"And I've just been working a lot since Spring Training," Leon said. "Just swing at strikes, keep it simple, don't try and do too much."
Leon might not be trying to do too much, but he's actually doing quite a lot.