Sania has been diagnosed with a ruptured left knee miniscus and has been initially advised a minimum six weeks rest by a specialist, who examined her in New York, according to information received here.
The Hyderabadi has been struggling with injuries in the last few seasons. She made a good comeback last year after a career-threatening wrist injury.
She zoomed up to 64 in the singles ranking after starting the 2011 season at 166. In the doubles list, she is at her career-best 11.
The latest injury means that Sania's place in the prestigious year-end Championships is also doubtful. Sania and her Russian partner Elena Vesnina are front runners in the race for the top-four doubles teams.
They are placed third in the race so far with 4508 points, followed by Argentine Gisela Dulko and Italian Flavia Pennetta, who have 4106.
There are still eight different WTA events, yet to be played in the 2011 season after the US Open, the last Grand Slam of the year.
Sania's campaign ended at the US Open when she and Vesnina lost 6-7 (4) 6-7 (5) to the Czech pair of Iveta Benesova and Barbora Zahlavova Strycova.
She had also lost in the first round of the singles and mixed doubles event with compatriot Mahesh Bhupathi.
Sania is expected in Hyderabad shortly to consult with Orthropaedic specialists, who will consider a surgical intervention after further intensive tests.
The Indian tennis player had undergone an arthroscopy to repair the ACL on her right knee a few years back.