What Are Torpedo Bats?

The torpedo bat, also called the bowling pin bat, is a new baseball bat design that became widely known during Major League Baseball’s opening weekend in March 2025 when the New York Yankees hit a franchise-record nine home runs in a single game. Fans quickly learned that six of those homers came from players who were using a novel, oddly oblong bat design.

The unconventional bat, which has a flared section in the middle of the barrel that tapers at the end instead of the standard straight barrel, was developed about 2023 by a then Yankees employee, Aaron Leanhardt. He had entered professional sports after receiving a Ph.D. in physics from the Massachusetts Institute of Technology and teaching that subject at the University of Michigan. Leanhardt came up with a design that, compared with the conventional bat, moves more of the bulk of the bat into the “sweet spot,” roughly 6–7 inches (15–18 cm) from the end of the barrel. This means that there is a larger surface area and more mass precisely where players prefer to make contact with the ball, potentially giving them a greater likelihood of getting hits and generating more power when they do. In addition, moving the bat’s center of gravity closer to players’ hands, thereby reducing the moment of inertia, affords them more control when swinging at a pitch.

In 2023 the Yankees began working with manufacturers to make prototypes, and several of the team’s players started using the torpedo bat with little fanfare during the 2023 and 2024 seasons. Behind the scenes, word of the new design—which is reportedly not eligible to be patented—spread, and manufacturers began supplying players on other teams with torpedo bats during spring training in 2025. Following the Yankees’ wild success on opening weekend, many more teams began adopting the new bat in the early weeks of the regular season.