The World number one and reigning Olympic champion was hoping to return to the country where he won Olympic glory this summer. However, he is struggling with a knee problem and wants to ensure he is fit to help his country win the David Cup.

Nadal was forced to abandon his quarterfinal game in the Paris Masters Series last week because of tendonitis in his knee.

"It is one of the decisions that has caused me the most pain, but I have decided not to attend the Masters Cup in Shanghai," explained the tennis player, who knew that the Chinese tennis fans would be disappointed.

"This is one of the toughest and difficult decisions that I have had to make in my career, both because of the importance of the event and above all, because I will not be able to be with the Chinese supporters."

"Although I have not yet undergone any tests yet, I know that I have taken the right decision. I want to be ready to play in the important date in Mar de Plata (the Davis Cup final) for my country."

"If I am not going to Shanghai, it is also for that," explained Nadal.

The Spaniard has played almost 120 competitive matches this season as well as exhibition games and in the end that has taken its toll.