BEIJING - Carlos Alcaraz added his voice to the criticism and pulled out of the Shanghai Masters with "physical issues" as the packed schedule for elite tennis players came under renewed scrutiny this week.
With another season approaching its climax, six-time major champion Alcaraz and fellow Grand Slam winners Iga Swiatek and Coco Gauff all took aim at the amount of tennis they play.
The busy calendar in women's and men's tennis has been a constant talking point in recent years.
Top players, who earn handsomely, have repeatedly railed against their workload and this week saw a raft of matches end prematurely at the China Open.
Five players retired from their matches in Beijing with injury on Monday alone.
On Tuesday there was the sight of Daniil Medvedev hobbling about on court, barely able to move, before the Russian called it quits when 0-4 down in the deciding set of his semi-final to US teenager Learner Tien.
Tien's quarter-final opponent, Lorenzo Musetti, also retired with injury.
One of the complaints among elite players has been that some tournaments, like Shanghai, have been extended to become more akin to a Grand Slam fortnight.
Critics have countered that the likes of Alcaraz have turned down opportunities to take a breather by playing lucrative exhibition matches instead.
This latter part of the season, when the tennis world heads to Asia, has seen other high-profile players struggle with injury or withdraw from tournaments.
The WTA insisted that "athlete welfare is always a top priority" in a statement to AFP.
"The new structure provides more predictability as to which events our top 30 players compete in and more playing opportunities for aspiring players, while underpinning the commitment to a $400 million increase in player compensation over the next 10 years," the statement said.