U.S. Open champion Naomi Osaka was drawn in the same group as Angelique Kerber, Sloane Stephens and Kiki Bertens for her debut appearance at the WTA Finals in Singapore.
Karolina Pliskova, defending champion Caroline Wozniacki, Petra Kvitova and Elina Svitolina are in the other group for the end-of-season tournament starting on Sunday.
Top-ranked Simona Halep is not playing because of a lower back injury. Serena Williams misses out, too, in a year in which she returned after giving birth to her first child and reached two Grand Slam finals.
There are five Grand Slam champions playing in Singapore: Osaka, Stephens, Kerber, Kvitova, and Wozniacki.
White Group: Karolina Pliskova, Caroline Wozniacki, Petra Kvitova, Elina Svitolina.
Red Group: Kiki Bertens, Naomi Osaka, Angelique Kerber, Sloane Stephens.
Source: The Associated Press