Sharapova hit by injury
Maria Sharapova has withdrawn from the end-of-season WTA Championships in Istanbul later this month.
The Russian pulled out of the US Open in August because of a right shoulder problem and has not competed since.
Sharapova said: "I am very disappointed that I will not be able to play in the TEB BNP Paribas WTA Championships this year.
"The fans in Istanbul have welcomed us each year with such intense passion and warmth, I will sincerely miss the energy and excitement they brought to the year-end tournament.
"I want to thank Istanbul for being a tremendous host and hope to play in Turkey sometime in the future."
Sharapova's withdrawal means former champion Petra Kvitova, Sara Errani and Jelena Jankovic have all qualified, the latter for the first time since 2010.
The trio join Serena Williams, Victoria Azarenka, Agnieszka Radwanska and Li Na, who had all already booked their places at the eight-woman showpiece, which begins on October 22.
That leaves one spot remaining, for which Angelique Kerber is in pole position.
The German took a late wild card into the tournament in Linz this week to try to secure her place.