Juan Martin Del Potro pulls out of US Open
Del Potro, who won the 2009 Open, underwent the procedure in March after battling wrist pain for more than a year.
The Argentine star has not played a match on tour since the Dubai Duty Free Tennis Championships in February.
Del Potro is ranked No. 11 in the world.
First-round play at the Open, which is held at the USTA Billie Jean King National Tennis Center in New York, begins August 25 and the tournament runs through September 8.
- Chris Johnson