Maria Sharapova, the 2006 United States Open champion, withdrew from the Open on Sunday, citing a leg injury.
Sharapova, a five-time major winner, has not played since her semifinal loss at Wimbledon in July against Serena Williams, withdrawing from tournaments in Toronto and Cincinnati, after sustaining the upper leg injury during her training for the hardcourt swing.
The third-seeded Sharapova, 28, was the highest-seeded player whom Serena Williams could have faced before the final as Williams looks to become the first player in 27 years to win the Grand Slam.
Sharapova had been scheduled to play her first match Monday evening in Louis Armstrong Stadium against Daria Gavrilova, a rising 21-year-old Russian-Australian who is ranked 38th and had beaten Sharapova this year in Miami.