Nadal to miss Davis Cup semis as injury layoff continues

(CNN) -- World No.3 Rafael Nadal will be out of action for at least two more months as he struggles to recover from a knee injury which has sidelined him since June.

The announcement of an extension to his rehabilitation means Nadal misses Spain's Davis Cup semifinal against the U.S. which starts on September 14th.

The Spaniard's last outing was at Wimbledon where he lost to Lukas Rosol in the second round.

Nadal announced the news on Twitter saying: "I have to recover and I'll be back once the pain is gone."

Rafael Nadal's injury heartache

An accompanying link to an official statement explained that Nadal has a "partial tear of the patella tendon" and "inflammation of the Hoffa's fat pad on his left knee."

Nadal reveals heartache at Games

Since the tear was diagnosed, Nadal has been receiving a range of therapies and medication to aid his recovery, according to the statement.

"I have missed the Olympics and the U.S. Open in the last few weeks, two of the most important tournaments of the year ..." Nadal said.

"I really want to get back competing ... I have many years in front of me and my knee needs some rest," he added.

Nadal's mind has been put at ease by recent meetings with his doctors, he says, adding that "the evolution of the past weeks has been positive and surgery has been avoided."

Angel Ruiz-Cotorro, doctor of the Royal Spanish Tennis Federation is scheduled to reveal more details about Nadal's injury at a press conference on Tuesday.