Reigning Olympic champion Rafael Nadal has been forced to withdraw from the London 2012 Olympics due to ongoing knee problems.

Nadal, gold medallist four years ago in Beijing admitted he was “not in the right physical condition to compete” and that he had to “think about Spanish sport.”

The world number two, who was due to carry Spain’s flag at the opening ceremony, had already taken two weeks off in the buildup to the Olympics to recover from tendinitis in his knee

“I’ve waited until the final moment of my preparation and my training, but I cannot do it,” Nadal said in a statement released to the Spanish press on Thursday.