Close-up of baseball bat in player's hand
"Torpedo bats," like the one shown here used by New York Yankees player Jazz Chisholm Jr., have a slightly bulbous shape that's similar to a bowling pin.
Ever since the New York Yankees hit nine home runs—a team record—against the Milwaukee Brewers on Saturday, the internet has been abuzz with chatter about the “torpedo bats” some players used during the staggering 20-9 win.
But what are torpedo bats, exactly? And how do they work?
To the untrained eye, torpedo bats don’t look all that different from standard bats. But to the athletes and coaches who live and breathe professional baseball, they represent a major advancement in the sport’s equipment.
“The same bat design has been in existence for a century and a half, maybe,” says Alan Nathan, a physicist at the University of Illinois Urbana-Champaign, to NPR’s Bill Chappell. “And to come up with something new, to me, is always very exciting.”
With a torpedo bat, the barrel—or the widest part of the bat—sits closer to the hitter’s hands. The bat is thinnest at the handle, then widens out at the barrel, then slims down toward the tip—sort of like a bowling pin.
Torpedo bats are custom-made for each player, with the barrel placed where that specific hitter tends to strike the ball—an area known as the “sweet spot.”
This means more wood—and, thus, more mass—at the area of the bat that will be making contact, increasing a player’s margin for error at that area. The goal is to help hitters connect with the ball on the bat’s barrel—at their specific sweet spot—more frequently. More sweet spot strikes, the thinking goes, translates to more hits and more homers.
Yes, the Yankees have a literal genius MIT Physicist, Lenny (who is the man), on payroll. He invented the “Torpedo” barrel. It brings more wood - and mass - to where you most often make contact as a hitter. The idea is to increase the number of “barrels” and decrease misses. pic.twitter.com/CsC1wkAM9G
— Kevin Smith (@KJS_4) March 29, 2025
Shifting the center of mass closer to the hitter’s hands reduces the bat’s “swing weight,” which can make it feel lighter and easier to control. In theory, this design change not only allows players to swing faster, but it also makes them more agile—they should be able to make quick adjustments to their swing once the ball leaves the pitcher’s hand. Moving the barrel down the bat might also make that area easier to see in the player’s peripheral vision, allowing them to line up their swing more accurately.
“Because you’re able to swing the bat faster, you have a little longer to watch the ball before you commit,” says Lloyd Smith, a mechanical engineer at Washington State University, to Scientific American’s Stephanie Pappas.
Even seemingly small adjustments can be helpful when pitchers are throwing balls at close to 100 miles per hour. Torpedo bats probably don’t help players hit the ball harder or faster. But the shifted barrel may help them hit more accurately, which should improve their overall batting average.
These nontraditional bats were developed by Aaron “Lenny” Leanhardt while he was working for the Yankees. (He’s now a field coordinator with the Miami Marlins.)
Leanhardt is a scientist. Before starting his baseball career in 2017, he earned a bachelor’s degree in electrical engineering from the University of Michigan and a doctorate in physics from MIT. After that, he was a physics professor at the University of Michigan for seven years.
Leanhardt came up with the idea for torpedo bats after talking with lots of players, who all wanted to make better contact with the ball and hit it with their bat’s sweet spot, reports the Athletic’s Brendan Kuty. He spent roughly two years honing his invention.
“It’s just through those conversations where you think to yourself, why don’t we exchange how much wood we’re putting on the tip versus how much we’re putting in the sweet spot?” Leanhardt tells the Athletic.
He adds: “It’s just about making the bat as heavy and as fat as possible in the area where you’re trying to do damage on the baseball.”
Some Major League Baseball (MLB) players began quietly using the bats in 2023 and 2024. But public awareness of them skyrocketed last weekend, after the Yankees’ monster day against the Brewers. Yankees players hit three home runs in a row—on the first three pitches in the game.
WHAT A START FOR THE @YANKEES!!!
3 pitches, 3 home runs!! pic.twitter.com/xWqAqH9X0y
— MLB (@MLB) March 29, 2025
Are torpedo bats legal? Officials have confirmed they don’t break any MLB rules, which require that a bat “shall be a smooth, round stick not more than 2.61 inches in diameter at the thickest part and not more than 42 inches in length. The bat shall be one piece of solid wood.”
It’s too early to tell whether the bats will measurably improve players’ performance. But, so far, they seem to be boosting the Yankees: The team has hit 17 home runs through their first four games, which is a new MLB record, per Bleacher Report’s Scott Polacek. (Though NPR notes that three of the Yankees’ nine homers were hit by Aaron Judge, who was using a regular bat.)
Regardless of the bats’ true efficacy, they do seem to be giving players a confidence boost—and that could be just as important.
“The game of baseball is so superstitious,” Dan Russell, an acoustics scholar at Penn State University, tells NPR. “It doesn’t matter what the thing is, if you found something that makes you more confident, it’s going to work.”
Yankees shortstop Anthony Volpe echoed that sentiment. He used a torpedo bat to hit a home run during the team’s win over the Brewers on Saturday.
“It’s probably just a placebo,” Volpe tells MLB.com’s Bryan Hoch. “A lot of it is just looking up at your bat and seeing how big the barrel is, but it’s exciting. I think any 0.01 percent mentally that it gives you confidence, it helps.”