Six-time Grand Slam champion Iga Swiatek said on Monday she might skip mandatory tournaments to protect her health after a string of injuries among players at the China Open.
The world number two from Poland reached the last 16 in Beijing after her Colombian opponent Camila Osorio retired hurt before their second set.
The number of matches in the tennis calendar has been a major talking point in recent years, with players such as Novak Djokovic cutting back the number of tournaments they compete in as they near the end of their careers.
"I don't know yet how my career is going to look like in a couple of years," the 24-year-old Swiatek said.
"Maybe I will have to choose some tournaments and skip them, even though they are mandatory," she added.
Starting last year, the Women's Tennis Association made it mandatory for top players to participate in each Grand Slam, 10 WTA 1000 events - which includes Beijing - and six 500-level tournaments.
"It's just impossible to squeeze it in the schedule," the former world number one said.
"I think we have to be smart about it, not really unfortunately care about the rules and just think what's healthy for us."
Swiatek called the requirements "pretty crazy" for top players, adding that "people are more fatigued" in the second half of the season.
"I think the Asian swing is the hardest part because you feel like the season is going to finish soon, but you still need to push," she said.
France's Lois Boisson also retired from her match Monday in the Chinese capital, and two other players quit mid-match in the women's singles draw a day earlier.
In the men's ATP 500 event also running in Beijing, Jakub Mensik retired during his quarter-final Monday.
Last week, men's world number one Carlos Alcaraz had a scare at the Japan Open in Tokyo when he landed awkwardly on his ankle.
"The only thing I can do now, when I decided I'm going to play all these mandatory tournaments, is to just take care of my body, take care of the recovery," Swiatek added Monday in Beijing.
"But yeah, there are a lot of injuries. I think it is because the season is too long and too intense."