Stosur topped Serena Williams in straight sets last year in winning her first Grand Slam title. She is ranked No. 7 as the . Open goes through the seeding and draw processes before beginning next Monday.
Li Na defeated Angelique Kerber in Sunday's final at the Western and South Open in Cincinnati. The result leaves Li in the No. 9 ranking slot but the finals appearance boosts Kerber to a career-high No. 6, pushing Stosur down to No. 7.
The winners of the year's first three Grand Slam events are ranked in the Top Four. No. 1-ranked Victoria Azarenka, who has 9,025 points, won the Australian Open while Maria Sharapova won the French Open and is ranked third with 7,695. Williams, ranked fourth, won at the Championships and the Olympics, both at Wimbledon, and has 7,300 points.
Agnieszka Radwanska, who lost to Williams in the finals at Wimbledon but has three tournament wins this year, is ranked second with 8,115 points.
Petra Kvitova (6,170) is No. 5 while Kerber has 5,715 points and Stosur is close behind with 5,700.
Caroline Wozniacki has 4,605 points for the No. 8 spot and Li has 4,570. Sara Errani (3,730) comes in 10th.