Nadal's attendance at ATP Tour Finals is shaky at best

Rafael Nadal says he does not know whether he will be fit to play the ATP Tour Finals, having withdrawn with a knee injury from the Paris Masters.

The Spaniard called the trainer for the injury during his third round win, and had also worn strapping on his knee for the final of Shanghai three weeks ago, deciding not to play his next scheduled event at Basel.

"I can not talk about London now. I am very disappointed about withdrawing from Bercy," he was quotedas telling press at Paris."It's not a good day to talk about London. All I can say is that I will take my treatment and I will do my maximum to play in London."

"For me, it's not about London, but about the longer term. I will do the treatment that I consider the safest to keep playing tennis as long as possible." He said he would go back to Spain and attend to the knee further before deciding whether to play again this season.

"I pushed my body," he said. "It's the finish of the season. It's normal that this type of thing happens. My knee always bother me, sometimes less, sometimes more – at the moment, it's more. I cannot play my usual level."

Nadal confirmed that the injury had affected him in the previous round in Paris.

"There was a lot of pain, but it was not the moment to retire," he said. "I had a treatment yesterday night to try to keep playing. Unfortunately, it's not possible.''

"The way I feel today, I could not play three matches like this. I came here to try to win the tournament, so if I don't have any chance, it's not a good idea."

However, with the wins he did get during the tournament, Nadal has secured his position at No. 1 for the rest of the season.

His withdrawal sends Filip Krajinovic into the semifinals.