Fourth-seeded Jannik Sinner withdrew from the Rolex Paris Masters on Thursday, with the event's scheduling serving as his reason.
His second-round match ended in the early hours of Thursday morning and his next match was slated for the same afternoon.
The 22-year-old Italian player said that the tight turnaround raised concerns about his health.
"I am sorry to announce that I am withdrawing from today's match in Bercy," Sinner posted on social media. "I finished the match when it was almost three in the morning and didn't go to bed until a few hours later. I had less than 12 hours rest to prepare for the next game."
Sinner finished his 6-7 (6), 7-5, 6-1 second-round win against Mackenzie McDonald at 2:37 a.m. local time.
His third-round match at the ATP 1000 event in the French capital was scheduled for Thursday afternoon against Alex de Minaur of Australia.
"I have to make the right decision for my health and my body," Sinner posted. "The weeks ahead with the ATP Finals at home and the Davis Cup will be very important, now I focus on preparing for these important events. See you in Turin."
Sinner already has qualified for the ATP Finals in Turin, Italy, which begin on Nov. 12. He is a 10-time winner on the ATP Tour.
Meanwhile, the 13th-seeded de Minaur advanced to the quarterfinals via a walkover and will face No. 5 Andrey Rublev of Russia.
—Field Level Media