Nadal, who crashed out of the US Open earlier this month suffering the same injury, said Sunday he was receiving treatment at his home in Mallorca.

‘I’m really sorry to announce I have to withdraw from the Thailand Open at this late date,’ Nadal said in a statement.

‘I had a knee injury during the US Open and hoped that it would clear up for the Thailand Open ... I have sought medical advice and have been advised to rest my knees for at least another few weeks,’  he said.

World number three and US finalist Novak Djokovic will take over as top seed, with American Andy Roddick second at Impact arena.

Both will arrive here fresh from Davis Cup duty in Europe, after Djokovic and his Serbian team battled Australia and the US, spearheaded by Roddick, took on Sweden in Gothenburg.

American James Blake chose not to defend his 2006 Thailand Open title.

Thai hopes this week rest with wild card Danai Udomchoke after compatriot and Thai number one Paradorn Srichaphan, ranked 155 in the world, continues to heal from wrist problems which have kept him off the court since March.

Djokovic, who has fast-tracked to three in the world, will play his first ATP event since losing the US Open final to Roger Federer.

The 20-year-old Serb returns to the Thai capital after first playing here in 2004, where he crashed out as a wild card in the opening round.

He takes on first up Russian Igor Kunytsin, with the winner of that match facing Asian number one Lee Hyung Taik of South Korea, or Amer Delic of the US.

Roddick reached the Bangkok final in 2004, where he lost to Federer as the Swiss master won the first of back-to-back Bangkok trophies, 6-4, 6-0.

Roddick has a first-round match with Wang Yeu-Tzuoo of Taiwan.

Czech third seed Tomas Berdych, another Davis Cup participant, starts against Thai wild card Kittipong Wachiramanowong.

German Davis Cup ace Tommy Haas takes the fourth seeding and will play veteran American Vince Spadea.

Carlos Moya of Spain, Russian Davis Cup player Dmitry Tursunov, Croatia’s Ivo Karlovic and Spain’s Fernando Verdasco round out the seedings.

Seeds:

Novak Djokovic (SRB x1)

Andy Roddick (USA x2)

Tomas Berdych (CZE x3)

Tommy Haas (GER x4)

Carlos Moya (ESP x5)

Dmitry Tursunov (RUS x6)

Ivo Karlovic (CRO x7)

Fernando Verdasco (ESP x8)