The year's final Grand Slam event will be held from Aug. 26 to Sept. 8.
The former No. 1 player from Switzerland and the 1997 U.S. Open champion, Hingis had surgery on May 20 to repair one torn ligament and three loose ligaments in her left ankle and was expected to be sidelined for about four months.
However, Hingis made a more rapid return from surgery than expected and is playing this week in the Rogers AT&T Canada Cup. She also is scheduled to play in the Pilot Pen Tennis event the following week.
Hingis, who will be 22 in September, won titles in two of her first three appearances in 2002, increasing her career total to 40. She claimed the Australian Open crown from 1997-99 and Wimbledon in 1997.
A five-time Grand Slam champion, Hingis was seeded No. 1 at the U.S. Open five straight years beginning in 1997.
Morariu, 24, was diagnosed with acute promyelocitic leukemia in May 2001 and began extensive chemotherapy treatment. She is in remission and returned to competitive play last month, participating in the World Team Tennis Professional League and tour-level events.
Morariu has been ranked as high as No. 29 in the world in singles and No. 1 in doubles during her career. She will play in her first Grand Slam tournament since the 2001 Australian Open, where she reached the doubles final with Lindsay Davenport and won the mixed doubles title with Ellis Ferreira.