World number two Iga Swiatek said the tennis season is too long and too intense, and the smart option for her would be to cut back on her schedule for the sake of her health, even if that means skipping mandatory tournaments.
The men's and women's circuits have faced criticism due to their 11-month seasons, and both the tours have come under fresh scrutiny during the "Asian swing" with five matches at the China Open unable to be completed on Monday due to injuries.
Camila Osorio retired after she dropped the first set to Swiatek, while Lois Boisson, Zheng Qinwen, Lorenzo Musetti and Jakub Mensik were unable to complete their matches in Beijing.
"I think people are more fatigued," six-time Grand Slam champion Swiatek told reporters.
"Unfortunately, the Asian Swing is the hardest part because you feel like the season is going to finish soon, but you still need to push.
"I don't know yet how my career is going to look like in a couple years. Maybe I will have to choose some tournaments and skip them, even though they are mandatory. The WTA, with these mandatory rules, they made this pretty crazy for us."
Top players are obliged to compete in all four Grand Slams, 10 WTA 1000 tournaments and six WTA 500 events under WTA rules, with the punishment for missing them ranging from rankings points penalties to fines.
"I don't think any top player will actually be able to achieve this ... It's impossible to squeeze it in the schedule," said Swiatek, who has committed to playing in all the mandatory events this year.
"We have to be smart about it, not really unfortunately care about the rules and think what's healthy for us. It's tough."
The WTA told Reuters that athlete welfare is a top priority and that it listened to views on the calendar, both through the players' council and their representatives on the WTA board, to improve the circuit structure in 2024 and boost compensation.
"These enhancements have been delivered without requiring players to commit to more events than the average number per season over the previous decade," the WTA said.
"The new structure provides more predictability as to which events top 30 players compete in and more playing opportunities for aspiring players, while underpinning the commitment to a $400 million increase in compensation over the next 10 years."
The WTA added it would continue to keep its tour structure under review based on feedback, while recognising that a review of the calendar requires coordination across governing bodies, including the ATP, ITF and Grand Slams.
The Professional Tennis Players' Association filed a lawsuit against the sport's governing bodies in March, with the advocacy group describing the situation as "unsustainable".
The WTA has said the lawsuit, which also accused the governing organisations of anti-competitive practices and a disregard for player welfare, was "baseless" and defended its record of growing the women's game.