The lingering debate on tennis balls used at ATP and WTA tournaments is a ball of confusion

“As soon as you play some shots with them, they go very big, much too fluffy. They become like a grapefruit. ... We’re basically playing 30-shot rallies because it’s almost impossible to hit a winner.” Daniil Medvedev, criticizing the “Head Tour” ball being used at the China Open

A tennis ball sanctioned for professional play measures only about two-and-a-half inches in diameter, and it weighs slightly more than two ounces, yet the tiny orb has become the elephant in the room when it comes to concerns about the rise in elbow, wrist, arm and shoulder injuries in the pro game.

Stories about the tennis balls used by the pros tend to be yawners. They have a whiff of Coke vs. Pepsi about them. But lately, there’s been a growing outcry over the role balls may be playing in fatigue and injury. And that makes for a different, more compelling tale than whether a certain ball is better suited for baseline or attacking play, or for clay or hard courts.

“There are some balls on the tour that just shouldn’t be played. They’re just not good enough,” Craig Boynton, the coach of Hubert Hurkacz, told me in a telephone interview. “I’ve seen guys show up at the next event after a tournament and their arms or shoulders are toast. That affects their ability to practice. Then they may have to get used to a different ball altogether. That can have a real effect.”

Medvedev is not the only player raising the alarm, nor is the Head ball used in Beijing the only one that has come under fire. In Beijing, Taylor Fritz responded to Medvedev’s broadside with a post on X, formerly Twitter: “ [I] have been dealing w[ith] wrist issues since the beginning of USO [US Open' series ‘cause of ball changes,” Fritz wrote. “We went [with] three different balls in three weeks.”

Many players share in the discontent but are resigned to living with the confusion. Carlos Alcaraz, the top seed but a semifinal loser in Beijing, told the press: “It is something tough, but the tennis player has to get used to that. It’s kind of a different feeling when you are coming into [every] tournament and it’s like, ‘What is going to be the ball?’”

The Australian Open is just one of many events that uses a Dunlop ball that has generated as much controversy as topspin. At this year’s tournament, Medvedev went into his third-round match with Sebastian Korda feeling a lot of wrist pain. But after losing the match Medvedev decided against talking about it. Then, after hearing repeated complaints in ensuing weeks, he cut loose in Doha. Citing injuries reported by Holger Rune, Stefanos Tsitsipas, Korda and others, Medvedev said that playing with the Dunlops was jarring, like “hitting apples.”

Medvedev told reporters: “I think this [use of the Dunlop ball] should be reconsidered.”

The current situation germinated a few decades ago, when tournament officials embraced the idea of slowing down the speed of the game in the interest of producing the long, exciting rallies we now witness daily. That led to slower surfaces—and less lively balls that are more difficult to clout for winners. But the danger of throwing the baby out with the bathwater is becoming increasingly evident as wave-after-wave of bigger, stronger, fitter, more equally-matched players—along with advances in equipment—reshape the game.

The greatest threat to the joints and muscles of a player’s arm comes from one simple action: striking the ball. The force of the hit, and the properties of the racquet, strings, and ball determine the amount of stress placed on the arm. The now ubiquitous “Extra Duty” ball has a heavier fiber nap than a standard ball. It fluffs up bigger, feels heavier on impact, and is conducive to longer points.

The “official ball” of the ATP Tour is the Dunlop AO but, oddly, tournaments are not obliged to use it. That’s because each event has the right to strike partnership deals with the ball manufacturer of its choosing. So, yes, it is all (or largely) about the money.

“The ball situation is something that could easily be fixed,” Boynton said, “But each tournament is independent and free to secure the best contract possible. There’s nothing we can do about it.”

In January, the Australian Open, sweeping aside repeated complaints from players, renewed its ball deal with Dunlop for another five years. No sooner was the deal publicized than defending champion Rafael Nadal was broadcasting his unhappiness with the ball.

“They [tournament officials] say [it] is the same, but the ball is worse quality, without a doubt,” Nadal said of the Dunlop AOs, “After a couple of hits, the ball loses the pressure. It’s more difficult to hit with the right spin.”

Others, including former champion Stan Wawrinka, backed Nadal.

“The ball situation is something that could easily be fixed. But each tournament is independent and free to secure the best contract possible. There’s nothing we can do about it.” - Craig Boynton, coach of Hubert Hurkacz

Boynton said that the poor quality of some balls really becomes obvious during the ball change regimen. (During a match, the balls are changed after the first seven games, then every nine games thereafter.)

“It’s really interesting, the integrity of the ball at the end of the change period is so different from the beginning,” he told me. “ It has forced people to implement strategies for dealing with that problem on the fly.”

Understandably, Grand Slams events use three different brands of ball due to the radical difference in their surfaces. Wimbledon is permanently wedded to Slazenger, which claims that its ball ball has a moisture repelling feature that make it more suitable for play on damp courts. Roland Garros used Dunlop balls for some years, but abandoned them (reportedly due to player complaints) and changed to Babolat in 2011. Many felt that those balls were too light (Boynton described them as “missiles”), so the French ultimately settled on (and currently use) a Wilson ball specially designed for red clay, the “Roland Garros.” The US Open is similarly conjoined with Wilson in a union uninterrupted—and rarely criticized by anyone—for nearly half-a-century.

Less understandable is why the tours don’t use the same balls in the run-up events as those majors. That might not sit well with either tournament marketers or ball makers, but it seems a reasonable goal for the overlords of tennis. Boynton suggested that the ITF and the pro tours should come up with two or three surface-specific balls and use them exclusively. The various ball makers could still manufacture them, or simply have their logos printed on the balls produced en masse elsewhere.

In a curious twist, until this year the women at the US Open played with regular, lighter Wilson balls. But last summer top players in the WTA, led by Iga Swiatek, mounted a successful drive to switch to the same, Extra Duty ball used by the men.

The experiment was a success for the majority, if not all, of the players. Wimbledon champion Marketa Vondrousova pulled out of the doubles after her round-of-16 singles win, citing arm pain due to the heavier balls. Ons Jabeur complained of a sore shoulder and only half-jokingly remarked, “I hope Iga is happy.”

Jabeur went on to say she grew up playing with anything and would continue to do so, “even rocks.” Medvedev feels like he’s already doing that.