The 26-year-old was forced to pull out of the US Open with the bursitis problem, on the same shoulder that required surgery in 2008, and she has since withdrawn from the Pan Pacific Open in Tokyo and the China Open to allow the injury to heal.
World No 4 Agnieszka Radwanska, who could overtake Sharapova in the rankings with a strong finish to the season, has also had her place in Istanbul confirmed, along with the doubles team of Sara Errani and Roberta Vinci who have qualified for the second successive year.
Sharapova’s 2013 season has been highlighted by Premier-level titles at Indian Wells and Stuttgart and three more finals (Miami, Madrid and the French Open).
This is the seventh time she has qualified for the WTA Championships – she is a one-time champion (2004) and two-time runner-up (2007, 2012).
Radwanska’s year has been highlighted by a Premier-level title at Sydney and two International-level titles at Auckland and Seoul, and she has been to one more final (Stanford).
This is the third time she has qualified for the WTA Championships – her best result was reaching the semi-finals last year.
The top eight singles players and top four doubles teams will compete in Istanbul for a record-setting $6 million prize money purse and the most prestigious title on the WTA calendar after the Grand Slams.