Who is Aaron Leanhardt and how did his 'torpedo' bat take over MLB?

[Kevin Barral]

The Marlins' new field coordinator attracted a huge crowd on Monday to discuss his role in designing the bats that are rapidly gaining popularity across the league.

MIAMI, FL—A former physics professor has been one of the most popular names in Major League Baseball during the first week of the 2025 regular season. Miami Marlins field coordinator Aaron Leanhardt, also known as "Lenny" or "El Torpedo," isn't used to showing his face to the world, but his innovative approach to bat design has captured everybody's curiosity.

"There's a lot more cameras here today than I'm used to," said Leanhardt on Monday when speaking to the media. "I'm used to walking behind all of this and someone else is standing here. It's definitely been a surreal couple of days."

Leanhardt's former team, the New York Yankees, leads the majors with 15 home runs so far this season. Many of them have been hit with customized bats that have unusual proportions, and it turns out Leanhardt was heavily involved in the research and production process.

"At the end of the day, it's about the batter, not the bat," said Leanhardt. "It's about the hitters and their hitting coaches, not their hitting implements, so I'm happy to always help those guys get a little bit better, but ultimately it's up to them to put good swings on good pitches and grind it out every day."

The torpedo bats being used by the Yankees have a similar length and weight as "normal" bats and follow MLB rules—the different appearance just comes taking some of the wood from the end of the bat and shifting it closer to the player's sweet-spot. Former Marlin Jazz Chisholm Jr., who is off to a hot start with a .417/.500/1.167/1.667 slash line and three homers, described it in a tweet:

Per Leanhardt, his conversations with major league and minor league players began leading into the 2023 season.

"They were definitely asking me questions and offering design advice and demoing them," said Leanhardt. "It's a feedback group. There's many different makes and models that have gone through this process, some of which never saw the field of play and some of which are hitting a lot of home runs right now."

The question that arises with this is why did it take so long for somebody to figure out that changing the traditional bat shape could benefit hitters?

"All I can say is that I was one of those smart guys for so long that they grew up swinging those old, weird-looking bats as well," said Leanhardt. "It wasn't until now that maybe anyone really thought about this, myself included. You show up every day, you put the glove on you're given, swing the bat that you're given, you put the spikes on that you're given and you go about your day as best as you can, and every now and then, it takes time to question what you're doing. Couple of years ago, some of the hitters started questioning what they were doing and I just kind of responded to their questions."

Leanhardt left the world of academia to begin his baseball journey in 2017, initially coaching in an independent league and at a community college. His time in Minor League Baseball started in 2018 as the New York Yankees rookie ball hitting coach. He wouldn't join their major league staff as an analyst until 2024.

This is Leanhardt's first season with the Marlins as field coordinator. He can be seen picking up the phone in the dugout during games when a close play is being considered for a managerial challenge, but his job involves much more than that.

"He's kind of the central point," said Marlins manager Clayton McCullough. "He's there with our group each day, bringing our strength and conditioning, on-field work, hitting, baserunning and what we're going to do on a daily basis. Lenny makes sure that every group is coordinated and synced up and what our work is going to look like from a schedule standpoint, during a homestand, series and then ultimately, in the dugout."

For all Marlins fans wondering if and when these bats will be used in Miami, it's already in the works. Per Leanhardt, expect to see them in action within the next several weeks.

"One of the big goals here is to be as innovative and on the leading edge of things as we possibly can be. This is certainly something that we're gonna look to be on the leading edge of. It's just been a quick offseason for everyone, lot of turnover and everything like that, so we're getting ramped up right now with it."

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