NEW YORK (AFP) Juan Martin del Potro, who underwent surgery earlier this year on his wrist, hopes to be healthy enough to defend his title at the US Open in August. The 21-year-old Argentinean was originally expected to miss the major championship because of surgery on his right hand. His recovery appears to be ahead of schedule so Del Potro was placed on the provisional Open entry list released Thursday by the United States Tennis Association. So far the only event he has competed in this year is the Australian Open. But tournament spokesman Tim Curry said world number seven Del Potro is practising and hitting balls again. Del Potro won his first Grand Slam title by rallying to beat five-time US Open champ Roger Federer in five sets in the 2009 final at Flushing Meadows. The US Open begins August 30.