The baseball world is going batty over the so-called “Torpedo” bats that contributed to the New York Yankees’ home-run barrage during their weekend series against the Milwaukee Brewers at Yankee Stadium.

The Bronx Bombers blasted a single-game record of nine home runs in a 20-9 romp over the Brewers on Saturday, followed by four more home runs in a series-sweeping 12-3 triumph on Sunday. 

It’s gotta be the bats.

Jazz Chisholm Jr., Cody Bellinger, Paul Goldschmidt, Austin Wells, and Anthony Volpe are among the Yankees using the Torpedo bat. They’ve combined to hit nine of the 15 home runs the Yankees smashed in the three-game series to open the season.

“It doesn’t feel like a different bat,” Mr. Chisholm told reporters. “It just helps you in a little way, I guess.”

The Torpedo bat first appeared last season. It differs from a traditional bat in that the barrel is closer to the hitter’s hands, making it more balanced from end to end. The idea is to increase the “sweet spot” where contact is normally made. “Obviously, the bigger the sweet spot, the bigger the margin for error,” Mr. Bellinger said.

The Yankees aren’t the only team using them. Tampa Bay infielder Junior Caminero and Minnesota Twins catcher Ryan Jeffers were also seen using the bats. Neither has a home run this season. According to Yahoo Sports, multiple bat companies are already manufacturing Torpedo bats for several major league teams.

Major League Baseball confirmed the bats are legal, conforming to Rule 3.02, which states that bats cannot be more than 2.61 inches in diameter and 42 inches in length.

“I started swinging this one in spring or before spring,” Mr. Bellinger said, “and I was like, ‘Oh, it feels good.’ It was an ounce lighter than the one I was swinging, but I think the way the weight was distributed felt really good.”

A former Yankees analyst and MIT physicist, Aaron Leanhardt, is credited with the design, created through conversations with players. Mr. Leanhardt, currently working in the Florida Marlins organization, told the Athletic the idea is to make the bat as fat as possible in actual hitting areas.

“That’s the original concept right there,” Mr. Leanhardt said. “Just try to take all that excess weight and try to put it where you’re trying to hit the ball, and then in exchange try to take the thinner diameter that used to be the sweet spot and put that on the tip.”

Yankees slugger Aaron Judge isn’t impressed. The reigning American League most valuable player doesn’t understand what all the fuss is about. After smashing 58 home runs last season, Mr. Judge used his traditional bat to belt four bombs, including a grand slam, in the three-game series against the Brewers. Three of the home runs came in Saturday’s historic win over the Brewers.

“There’s a lot of new things in the game,” Mr. Judge said. “You’ve got the Torpedo bats, you’ve got so many different things. Hopefully, as my career goes on, maybe I could start adding some of those if I start losing something. But I think we’re good where we’re at now.”

The Brewers’ lack of pitching prowess may have contributed to the Yankees’ home run assault. Eight of their top 13 pitchers were not available for the series. Former Yankees starter Nestor Cortes was awful on Saturday, surrendering five home runs, while two other Milwaukee pitchers made their major league debut.  The Brewers pitching staff left Yankee Stadium with a 12.75 ERA.

“This is the way it is right now,” Brewers manager Pat Murphy said during the weekend. “We’re beat up. We’re hurt. We’ve got to go through it.”

Meanwhile, Brewers reliever Trevor Megill, called the bats “terrible” and “genius” after pitching a scoreless one-third of an inning against the Yankees.  “I’ve never seen anything like it before,” Mr. Megill said. “I feel like it’s something used in slo-pitch softball. It’s genius: Put the mass all in one spot. It might be bush (league). It might not be. But it’s the Yankees, so they’ll let it slide.”

The Yankees open a three-game series in Arizona on Tuesday.