Sharapova said: "I am very disappointed that I will not be able to play in the 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."
Due to Sharapova's withdrawal it means that former champion petro Kvitova, Sara Errani and Jelena Jankovic have all qualified. They join Serena Williams, Victoria Azarenka, Agnieszka Radwanska and Li Na, who had all already booked places at the WTA Championships, which begins on 22 October.
Only one spot remains at this tournament where Angelique kerber is in pole position.