Tommy Haas' bid to become the oldest man in the French Open's second round since Jimmy Connors in 1991 ended after less than a set on Tuesday because of pain in his right shoulder.
Now the question for the 36-year-old German, a four-time Grand Slam semifinalist, becomes how much longer he will put up with the injury.
"If it continues to go on like this, who knows? It's a tough task to continue and to see doctors every other week to try to just be able to play a tournament here or there or finish a tournament or finish matches now," Haas told The Associated Press. "We'll have to see. It's frustrating."
The 16th-seeded Haas stopped playing while leading 5-2 in the opening set of his first-round match at Roland Garros against 335th-ranked Jurgen Zopp of Estonia.
"I felt it on one shot at 5-2, and that was it. I felt a little something in the shoulder. I couldn't really do the motion anymore that I need to create power and to feel good," Haas said. "Nobody knows your body as well as yourself, so it's tough to understand from the outside. But I just know that something is not right. ... I need some rest and more rehab and will see if I can get it back on track again."
Haas, who reached the quarterfinals at last year's French Open, got to a career-best ranking of No. 2 in 2002. But he then missed all of the following year and part of 2004 because he twice needed surgery on his right shoulder.
At his last tournament, the Italian Open, Haas quit after the first set of his quarterfinal May 16 because the shoulder was bothering him.
"The wear and tear and the recovery process for that shoulder is obviously much, much harder to do," Haas said. "With the history of problems that I've had, it's not too easy. But you try til the last chance you get, in order to get it back on track and just to see if you can play matches without too much pain."
Another seeded player in his section of the draw, No. 21 Nicolas Almagro, also retired during a first-round match Tuesday, allowing 21-year-old Jack Sock, who's from Nebraska, to advance. Almagro, a three-time French Open quarterfinalist, stopped while trailing 5-0 because of a left foot injury he said has been bothering him for six weeks.
"I came here knowing I would not be 100 percent, for sure, but I thought I could be at 60, 70, 80 percent, and I would try to do my best," said Almagro, one of three men to defeat Rafael Nadal on clay this season. "But in the first set, I felt it again and the pain was terrible. It was impossible to keep playing."
The 75th-ranked Sock next faces either Laurent Lokoli, a 19-year-old qualifier from France who is ranked 406th, or 64th-ranked American Steve Johnson.