Reigning Olympic champion Rafael Nadal pulls out of London 2012

Rafael Nadal won gold for Spain at the Beijing Olympics four-years ago (GETTY IMAGES)

Rafael Nadal, the reigning Olympic champion, has pulled out of the London 2012 Games.

The Spaniard will not compete due to injury, saying the decision to withdraw "is one of the saddest days" of his career.

"I am not able to compete at the Olympics in London and therefore will not be traveling as planned with the Spanish delegation," he said in a statement on the Spanish federation (RFET) website.

"I have to think about my colleagues. I cannot be selfish and I have to think of the good of Spanish sport, especially Spanish tennis, and let a team-mate who is better prepared to compete.

"I've waited until the final moment of my preparation and my training, but I cannot do it."

The world number three, who was was due to be the flag bearer for his country at the opening ceremony and was among their best hopes for a gold medal, expressed his disappointment.

"Today is one of the saddest days of my career.

"Perhaps one of the most special moments was to be Spain's flagbearer in the opening ceremony for the Games in London, so you can imagine how difficult it has been making this decision. "

The 26-year-old's last regular tournament was Wimbledon, the venue for the Olympic tennis tournament, where he suffered a shock second round defeat to world number 100 Lukas Rosol.

He will now be unable to defend the gold medal he won in Beijing four years ago.

RFET president Jose Luis Escanuela was also devastated, saying: "It's the worst news we could have.

"Rafa has always been an example of perseverance and tenacity, which makes it hard to miss out because surely would have loved to return to the Games. I hope he recovers quickly."

Roger Federer and Novak Djokovic will be the favourites to win gold at London 2012, while Andy Murray will be odds on to claim at least a bronze for Great Britain following Nadal's withdrawal.