Defending champion Juan Martin del Potro withdrew from the U.S. Open on Saturday, saying he "cannot compete at the top level yet" after having an operation on his right wrist in May.
He becomes only the third U.S. Open men's champion in the 42-year Open era who didn't defend the title. And del Potro's announcement arrives a day after Serena Williams became the first No. 1 in the 35-year history of the women's rankings to miss the U.S. Open. She still is recovering from surgery for cuts on her right foot.
The 6-foot-6 del Potro has not played on tour since the Australian Open in January because of an injury to his right, racket-swinging wrist. The 21-year-old Argentine had surgery in May, then recently began training in hopes of playing at Flushing Meadows, where he won his first major championship a year ago by upsetting Rafael Nadal in the semifinals and Roger Federer in the final.
In a statement released by the ATP on Saturday, del Potro said he is "extremely sad" about pulling out of the year's last Grand Slam tournament, which starts Aug. 30.
"But I have only started practicing in the last two weeks and unfortunately I cannot compete at the top level yet," he said. "I look forward to returning to New York in 2011 and wish all the best to the tournament organizers and my fellow players."
Since 1968, the only other men who didn't defend U.S. Open titles were Ken Rosewall in 1971 and Pete Sampras in 2003. Sampras retired after winning the 2002 U.S. Open in his final match as a professional.
Del Potro's right wrist has been a problem since last year; he retired in the second round of the Shanghai Masters in October because of tendinitis in the wrist. In January, he pulled out of an exhibition tournament just days before the start of the Australian Open, citing the wrist.
He lost in the fourth round at Melbourne, and hasn't entered a tournament since. Del Potro is No. 9 in this week's rankings but will slide from there after the U.S. Open because he will lose the ATP points that came with his 2009 title.
"It would have been a pretty tall task for him to come back and (at) his first tournament be a major player," 2003 U.S. Open champion Andy Roddick said. "That's something that's built up over time."
In late July, del Potro was on the provisional entry list released by the USTA for the men's field at the 2010 U.S. Open. In a statement then, the USTA said del Potro was "expected to return to Grand Slam competition" at the U.S. Open.
"It is unfortunate that Juan Martin has not recovered from wrist surgery in time to defend his U.S. Open title," tournament director Jim Curley said Saturday. "We wish him all the best and look forward to his return to New York next year."
Now del Potro's return to the tour could come at the Thailand Open, an indoor tournament that begins Sept. 24 in Bangkok. Del Potro said in July he planned to play in that event.
In addition to del Potro and Williams — the three-time U.S. Open champion who cut her foot in July shortly after winning Wimbledon — the American Grand Slam tournament will be without two-time champion Justine Henin. Three other past U.S. Open winners — Venus Williams, Maria Sharapova and Kim Clijsters — have been injured recently.
Two other men withdrew late Friday: No. 10-ranked Jo-Wilfried Tsonga and three-time U.S. Open quarterfinalist Tommy Haas.
AP Sports Writer Joe Kay in Mason, Ohio, contributed to this report.