Andy Roddick and Juan Carlos Ferrero have been forced to pull out of the French Open with shoulder injuries.
Roddick, who has never got beyond round four at Roland Garros, withdrew from this week's Nice Open after a painful right shoulder at the Rome Masters.
Ferrero, 2003 French Open champion, had surgery on his right wrist and left knee last year and only recently returned from a six-month lay-off.
Injured Richard Berankis will also miss the tournament, which starts on Sunday.
It is the latest blow for Roddick, ranked 11 in the world, who opted not to play in last weekend's Italian Open doubles final and in Nice to give himself every opportunity to recover for the French Open.
The American, US Open champion eight years ago and Wimbledon runner-up three times, has lost his last four singles since the middle of March.
Ferrero had also been hoping to continue his recovery in Paris after returning to action in Barcelona in April.
The former world number one and current number 73 suffered a first-round defeat by Dutch qualifier Thiemo De Bakker at the recent Madrid Open.
The 31-year-old admitted after his three-set loss: "My performance wasn't good, and when you're on court and you see how different you are now compared to how you were before, it's difficult to get over that."