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.

Read: An MIT-educated professor, the Yankees and the bat that could be changing baseball

What is a torpedo bat and why is it different from a traditional MLB bat?

The idea of the torpedo bat is to take a size format — say, 34 inches and 32 ounces — and distribute the wood in a different geometric shape than the traditional form to ensure the fattest part of the bat is located where the player makes the most contact. Standard bats taper toward an end cap that is as thick diametrically as the sweet spot of the barrel. The torpedo bat moves some of the mass on the end of the bat about 6 to 7 inches lower, giving it a bowling-pin shape, with a much thinner end.

How does it help hitters?

The benefits for those who like swinging with it — and not everyone who has swung it likes it — are two-fold. Both are rooted in logic and physics. The first is that distributing more mass to the area of most frequent contact aligns with players’ swing patterns and provides greater impact when bat strikes ball. Players are perpetually seeking ways to barrel more balls, and while swings that connect on the end of the bat and toward the handle probably will have worse performance than with a traditional bat, that’s a tradeoff they’re willing to make for the additional slug. And as hitters know, slug is what pays.

The second benefit, in theory, is increased bat speed. Imagine a sledgehammer and a broomstick that both weigh 32 ounces. The sledgehammer’s weight is almost all at the end, whereas the broomstick’s is distributed evenly. Which is easier to swing fast? The broomstick, of course, because shape of the sledgehammer takes more strength and effort to move. By shedding some of the weight off the end of the torpedo bat and moving it toward the middle, hitters have found it swings very similarly to a traditional model but with slightly faster bat velocity.

Why did it become such a big story so early in the 2025 MLB season?

Because the New York Yankees hit nine home runs in a game Saturday and Michael Kay, their play-by-play announcer, pointed out that some of them came from hitters using a new bat shape. The fascination was immediate. While baseball, as an industry, has implemented forward-thinking rules in recent seasons, the modification to something so fundamental and known as the shape of a bat registered as bizarre. The initial response from many who saw it: How is this legal?

OK. How is this legal?

Major League Baseball’s bat regulations are relatively permissive. Currently, the rules allow for a maximum barrel diameter of 2.61 inches, a maximum length of 42 inches and a smooth and round shape. The lack of restrictions allows MLB’s authorized bat manufacturers to toy with bat geometry and for the results to still fall within the regulations.

Who came up with the idea of using them?

The notion of a bowling-pin-style bat has kicked around baseball for years. Some bat manufacturers made smaller versions as training tools. But the version that’s now infiltrating baseball goes back two years when a then-Yankees coach named Aaron Leanhardt started asking hitters how they should counteract the giant leaps in recent years made by pitchers.

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.

At 1:54 ET on Saturday afternoon, New York Yankees play-by-play man Michael Kay lit the fuse on what will be remembered as either one of the most metamorphic conversations in baseball history or one of its strangest.

During spring training, someone in the organization had mentioned to Kay that the team’s analytics department had counseled players on where pitches tended to strike their bats, and with subsequent buy-in from some of the players, bats had been designed around that information. In the hours before the Yankees’ home game against the Brewers that day, Kay told the YES Network production staff about this, alerting them so they could look for an opportunity to highlight the equipment.

After the Yankees clubbed four homers in the first inning, a camera zoomed in on Jazz Chisholm Jr.‘s bat in the second inning. “You see the shape of Chisholm’s bat…” Kay said on air. “It’s got a big barrel on it,” Paul O’Neill responded, before Kay went on to describe the analysis behind the bat shaped like a torpedo.

Chisholm singled to left field, and after Anthony Volpe worked the count against former teammate Nestor Cortes to a full count, Volpe belted a home run to right field using the same kind of bat. A reporter watching the game texted Kay: Didn’t he hit the meat part of the bat you were talking about — just inside where the label normally is?

Yep, Kay responded. Within an hour of Kay’s commentary, the video of Chisholm’s bat and Kay’s exchange with O’Neill was posted on multiple platforms of social media, amplified over and over. What happened over the next 48 hours was what you get when you mix the power of social media and the desperation of a generation of beleaguered hitters. Batting averages are at a historic low, strikeout rates at a historic high, and on a sunny spring day in the Bronx, here were the Yankees blasting baseballs into the seats with what seemed to be a strangely shaped magic bat.

An oasis of offense had formed on the horizon, and hitters — from big leaguers to Little Leaguers, including at least one member of Congress — paddled toward it furiously. Acres of trees will be felled and shaped to feed the thirst for this new style of bats. Last weekend, one bat salesman asked his boss, “What the heck have we done?”

Jared Smith, CEO of bat-maker Victus, said, “I’ve been making bats for 15, 16 years. … This is the most talked-about thing in the industry since I started. And I hope we can make better-performing bats that work for players.”

According to Bobby Hillerich, the vice president of production at Hillerich & Bradsby, his company — which is based in Louisville, Kentucky, and makes Louisville Slugger bats — had produced 20 versions of the torpedo bat as of this past Saturday, and in less than a week, that number has tripled as players and teams continually call in their orders.

The best start in Dodgers history stays with Brooklyn.

The World Series champions ran themselves out of a shot at keeping their undefeated season alive in a 3-2 loss to the Philadelphia Phillies on Friday that stuck them at 8-1 on the season.

The Brooklyn Dodgers got off to a 10-0 start in 1955.

This year’s Dodgers can blame their first loss on sloppy and silly baserunning.

“When you give a good team outs and shorten the game,” manager Dave Roberts said, “then it’s hard to win. It’s hard to beat a good team.”

Shohei Ohtani always has the green light to run, but the Dodgers superstar made the puzzling decision to try to steal second base with two outs in the eighth inning and eight-time All-Star Mookie Betts at the plate. Phillies catcher J.T. Realmuto nailed him at second to end the threat.

Ohtani had a 93.7% stolen base success rate last season, third-best in the majors.

“With Shohei in that situation, you’ve got to make sure you’re safe,” Roberts said. “Realmuto is one of the best throwers in the game. When you’re down three with Mookie at the plate, you’ve got to make sure you’re safe if you’re going to go.”

The Dodgers are champs for a reason and wouldn’t go down easy.

Tommy Edman hit a two-run homer, his fifth this season, with no outs against Phillies reliever Jordan Romano to make it 3-2, as the Dodgers avoided being shut out for the first time since July 26. Romano then escaped on a strike-him-out, throw-him out double play to end the game. Pinch-hitter Max Muncy whiffed, and pinch-runner Chris Taylor was out at second.

“Chris, right there, took a chance,” Roberts said. “Unfortunately, Realmuto made another great throw.”

For added baserunning embarrassment, Andy Pages was picked off to end the sixth inning.

“We hate losing, but I think it does go to how we play,” Roberts said. “Giving those guys three outs on the bases, it’s hard to win when you play eight innings on the offensive side. That’s something we have to clean up.”

Realmuto has now thrown out three runners in a two-game span for the fifth time in his career and first time since 2022.

“The Ohtani one surprised me a little bit just because Mookie was hitting,” Realmuto said. “When Chris ran, I had a pretty good idea he was going to try to run because he’s the tying run and he’s usually a pretty good stolen-base guy.”

Everything had gone right for the Dodgers this season.

Ohtani hit a tiebreaking home run in the ninth inning on his bobblehead night, lifting the Dodgers over the then-winless Atlanta Braves 6-5 on Wednesday to give them the best start ever by a defending World Series champion. They have trailed in seven games this season but already have two walk-off wins. Ohtani failed to score for the first time this season.

With the Phillies up 1-0 in the seventh, starter Jesus Luzardo got into his only jam of the game when he had two runners on base with two outs. Luzardo, who had his fastball humming in the high 90s, got Kiké Hernández to strike out swinging on a slider to that had another sellout crowd at Citizens Bank Park roaring in celebration. Hernández fanned three times.

Dodgers starter Yoshinobu Yamamoto struck out five and allowed one unearned run in six innings. The unearned run came on his own error. Yamamoto threw the ball into foul territory trying to pick off Trea Turner attempting to steal third in the first inning. The All-Star shortstop hustled home for a 1-0 lead.

Yamamoto tossed at least six innings without allowing an earned run for the fourth time in his career and first time since June against the New York Yankees.

Information from ESPN Research and The Associated Press was used in this report.