Rafael Nadal has withdrawn from the AEGON Championships at Queen's and faces a battle to be fit for Wimbledon.

The World number one and defending champion, a surprise fourth-round casualty at the hands of Robin Soderling in the French Open, has been advised by doctors to rest because of ongoing knee problems.

The Spaniard said: "I have been having some problems in the past months with my knees, that's no secret, that have not allowed me to always compete at 100%.

"I need to work with my team to recover well, work on my physical condition to be at my top form and get ready for the grass to play at Wimbledon.

"I hope I can be ready to compete by then."

He added: "I am very disappointed to miss Queen's, and not defend the title I won last year. I enjoy playing there in front of the very knowledgeable British crowds."

The 23-year-old won the title at Queen's last year despite arriving the day after claiming the French Open crown.

He then went on to beat then world number one Roger Federer in an epic final to claim his first Wimbledon title.

Tournament director Chris Kermode said: "He has been a huge favourite with the crowds here at The Queen's Club over the past three years.

"No-one is more disappointed than Rafa himself, but his health must come first.

"For the past three years he has played his heart out here only a couple of days after winning the French Open, so we know that he has not taken this decision lightly."

British number one Andy Murray will now be the highest-ranked player in the tournament, while former world number ones Andy Roddick, Lleyton Hewitt and Marat Safin will all compete.

Organisers earlier today announced 2006 Australian Open finalist Marcos Baghdatis had been given a wild card.