Former World No.1 Rafael Nadal has underlined the fact that he will not return to the tennis circuit until his knee is completely healed.

"I have to listen (to the doctors) and be patient, anent d I will come back when my knee is well," the third-ranked Spaniard said yesterday from his home island of Mallorca.

"The best thing I can do now is to stop, get fully well, accept the situation and work hard to come back better."

Nadal has been out of the playing circuit since his defeat in the second round at Wimbledon againt Lucas Rosol.

The 26-year-old Nadal missed the Olympics, where he was set to defend his gold medal and carry Spain's flag at the opening ceremony. He also missed a charity match with Novak Djokovic and tournaments in Toronto and Cincinnati before recently ruling himself out of the upcoming US Open.

The 11-time Grand Slam winner said that he was not worried about falling down the world rankings.

"At this stage in my career my ranking is of the least importance," Nadal said. "The most important thing is that I am sure I am fit to compete like I did during the first six months of this year, with a solid chance to win in each tournament I enter. After being almost eight years ranked either first or second, I think that being ranked second or fourth or sixth doesn't really change anything."

Nadal peculiar playing style has landed his knees in trouble before also. In 2009, the Spaniard took a hiatus, recovered and came back much stronger than before.

Nadal reiterated his desire to play in the Davis Cup semifinal against USA, starting on September 14, but he made no commitments.

"If (my knee) is well in time for the Davis Cup and the captain wants me, I will be happy to be there," he said. "It would be exciting for me and a great moment to return. If not, then I will have to wait a little longer."