Former world number one Andy Roddick has emerged as a doubt for the French Open later this month due to a hamstring injury.
The American 29-year-old was forced to withdraw from next week's Madrid Open as well as the Rome Masters, due to take place before the contest in Paris.
Roddick will be able to test his fitness in the AEGON Championships, which are due to go ahead the week before the Roland Garros, before deciding on whether to compete in the tournament.
Meanwhile, Novak Djokovic is expected to return to action in Madrid after pulling out of the Serbian Open due to his grandfather's death.
