What’s that circular object on a baseball bat?

Fans of Major League Baseball might have noticed players swinging a bat with a strange device fixed to it during warm-ups. It resembles a ring placed near the middle or upper part of the bat, but is removed before stepping up to the plate.

Is it a bat cover designed to keep the bat warm? Or perhaps a device to prevent theft?

Actually, it's a bat doughnut, and while there’s no conclusive proof, it’s believed to improve a player’s hitting performance.

The concept behind using a weighted bat for warm-ups is that batters who first swing a heavier bat, then switch to a lighter, regular bat, will feel the difference and swing faster and harder due to the lighter weight. These doughnuts, which range in weight from 4 to 28 ounces, easily slide on and off the bat. Some players opt for specially designed weighted bats, which can weigh as much as 55.2 ounces—much more than a standard 31.5-ounce bat. Many begin using doughnuts at the Little League level (although doughnuts are banned, weighted bat sleeves are allowed). Others may even go the classic route and swing multiple bats simultaneously to achieve the same effect.

However, it seems that tradition may hold more weight than science. In 2011, researchers from California State University, Fullerton conducted a study with 19 volunteers, who used light, regular, and heavy bats before heading to the plate. The results showed that using a heavier bat didn’t enhance their performance with a regular bat. In fact, it slowed them down, with their bat speed dropping to 77.2 kilometers per hour compared to 83.7 kilometers per hour after using a lighter bat or 80.5 kilometers per hour with the regular bat during practice.

The origins of the bat doughnut are somewhat unclear. In 1967, a New Jersey construction worker named Frank Hamilton found the idea of swinging multiple bats absurd, so he invented a weight attachment. Hamilton approached Elston Howard, the first Black player on the New York Yankees, who lived nearby, to help promote the product, which they named Elston Howard’s On-Deck Bat Weight. Famous players like Mickey Mantle and Willie Mays took interest, and the doughnut quickly became a fixture in the dugout.

Whether or not it’s truly effective might not matter. In baseball, there’s something unbeatable about a solid ritual.