Rafael Nadal's participation at this year's Wimbledon has been thrown into doubt after his coach admitted that there is 'no fixed date' for his return to action.

The 30-year-old was forced to withdraw from the French Open in round three last month because of a wrist injury and subsequently pulled out of Wimbledon warm-up tournament Queen's.

Initially it was believed that Nadal could make his return at the All England Club at the end of the month, but coach/uncle Toni Nadal has now suggested that he may not be fit in time.

"He is in the phase of rehabilitation. We haven't fixed a date for his return because the important thing is that he returns at full strength," he told Sky Sports News.

"We also don't want to put in danger his participation in the Olympic Games.

"He will return when the doctors are convinced that all is going well. He won't play unless he's 100%."

Former world number one Nadal has 14 Grand Slams to his name, including two Wimbledon titles.