The opening weekend of the 2025 MLB season was taken over by a surprise star — torpedo bats.

The bowling pin-shaped bats became the talk of the sport after the Yankees’ home run onslaught on the first Saturday of the season put it in the spotlight and the buzz hasn’t slowed since.

What exactly is a torpedo bat? How does it help hitters? And how is it legal? Let’s dig in.

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When Yankees players responded that bigger barrels would help, Leanhardt — an MIT-educated former Michigan physics professor who left academia to work in the sports industry — recognized that as long as bats stayed within MLB parameters, he could change their geometry to make them a reality. Leanhardt, who left the Yankees to serve as major league field coordinator for the Miami Marlins over the winter, worked with bat manufacturers throughout the 2023 and 2024 seasons to make that a reality.

When did it first appear in MLB games?

It’s unclear specifically when. But Yankees slugger Giancarlo Stanton used a torpedo bat last year and went on a home run-hitting rampage in October that helped send the Yankees to the World Series. New York Mets star Francisco Lindor also used a torpedo-style bat last year and went on to finish second in National League MVP voting.

Who are some of the other notable early users of torpedo bats?

In addition to Stanton and Lindor, Yankees hitters Anthony Volpe, Austin Wells, Jazz Chisholm Jr., Cody Bellinger and Paul Goldschmidt have used torpedoes to great success. Others who have used them in games include Tampa Bay’s Junior Caminero, Minnesota’s Ryan Jeffers and Toronto’s Davis Schneider. And that’s just the beginning. Hundreds more players are expected to test out torpedoes — and perhaps use them in games — in the coming weeks.

How is this different from a corked bat?

Corking bats involves drilling a hole at the end of the bat, filling it in and capping it. The use of altered bats allows players to swing faster because the material with which they replace the wood — whether it’s cork, superballs or another material — is lighter. Any sort of bat adulteration is illegal and, if found, results in suspension.

Could a rule be changed to ban them?

Could it happen? Sure. Leagues and governing bodies have put restrictions on equipment they believe fundamentally altered fairness. Stick curvature is limited in hockey. Full-body swimsuits made of polyurethane and neoprene are banned by World Aquatics. But officials at MLB have acknowledged that the game’s pendulum has swung significantly toward pitching in recent years, and if an offensive revolution comes about because of torpedo bats — and that is far from a guarantee — it could bring about more balance to the game. If that pendulum swings too far, MLB could alter its bat regulations, something it has done multiple times already this century.

So the torpedo bat is here to stay?

Absolutely. Bat manufacturers are cranking them out and shipping them to interested players with great urgency. Just how widely the torpedo bat is adopted is the question that will play out over the rest of the season. But it has piqued the curiosity of nearly every hitter in the big leagues, and just as pitchers toy with new pitches to see if they can marginally improve themselves, hitters will do the same with bats.

Comfort is paramount with a bat, so hitters will test them during batting practice and in cage sessions before unleashing them during the game. As time goes on, players will find specific shapes that are most comfortable to them and best suit their swing during bat-fitting sessions — similar to how golfers seek custom clubs. But make no mistake: This is an almost-overnight alteration of the game, and “traditional or torpedo” is a question every big leaguer going forward will ask himself.