Serena Williams, who had lost the world No. 1 ranking last year but regained it by winning the Australian Open in January for her record 23rd Grand Slam title, withdrew from the BNP Paribas Open on Tuesday.
Williams, 35, cited pain in her knees for pulling out of the tournament, which will start Wednesday at the Indian Wells Tennis Garden. She was the runner-up last year.
“Sadly, I have to withdraw from the BNP Paribas Open in Indian Wells and the Miami Open,” Williams said in a statement issued by tournament officials. “I have not been able to train due to my knees and am disappointed I cannot be there. I will keep moving forward and continue to be positive. I look forward to being back as soon as I can.”
The singles draw was being revised Tuesday afternoon. Last year’s champion, Victoria Azarenka, also won’t compete because she’s taking time off after giving birth to a son in December.
Williams had cited pain in her left knee as a contributing factor in her semifinal loss to Karolina Pliskova at the U.S. Open last September. That defeat led to the end of her 186-week reign atop the rankings, a spot that was taken over by Angelique Kerber.
However, Williams regained the No. 1 spot after she won the Australian Open without losing a set, defeating her sister, Venus, 6-4, 6-4, in the final at Melbourne. Williams has not played in a tournament since then.
According to the sport’s points system, Kerber will be No. 1 in the next rankings, which will be issued March 20.
As a result of Williams’ withdrawal, the women’s draw was adjusted to place No. 3 seed Karolina Pliskova into Williams’ previous slot at the top of the draw sheet. No. 5 seed Dominika Cibulkova moved from the bottom half of the draw to the top and No. 9 Madison Keys moved into Cibulkova’s previous spot.
The men’s draw, done Tuesday, put world No. 1 and top-seeded Andy Murray on the same side of the draw as No. 3 Stan Wawrinka. No. 2 Novak Djokovic, the defending champion, is in the bottom half of the draw. His quarter includes Rafael Nadal, No. 9 seed Roger Federer, Juan Martin Del Potro, Alexander Zverev and Nick Kyrgios.
6:35 p.m.: This article was updated with details about the adjusted draws.
This article was originally published at 3:10 p.m.