Rafael Nadal unlikely for ATP World Tour Finals after Paris Masters exit

World No. 1 Rafael Nadal is unlikely to participate in the year-ending Nitto ATP World Tour Finals in London, Great Britain later this month. On Friday, the Spaniard was forced to pull out of his Paris Masters quarter-final match against Serbia's Filip Krajinovic due to a persisting knee injury.

At 31, Nadal is set to become the oldest player in ATP Rankings History to finish a year at World No. 1 when he's presented with the trophy at the Nitto ATP Finals (Nov. 12-19). However, it seems like Nadal won't be available for the presentation ceremony.

Rafael Nadal unlikely for ATP Finals in London

Nadal has been advised rest by Angel Ruiz Cotorro, his family doctor. "You always have to be optimistic, but also realistic, you have to see that we are at the end of the year, after an extraordinary season.

“Now he suffers some small discomforts within a pathology that we already know, in a tendon in which he has already had ailments in other occasions, and we will try to do everything possible so that he can be in good condition, because he wants to be, is the only tournament he's missing," Cotorro is quoted as saying by Spanish outlet El Larguero.

Nadal, who captured the French Open and US Open to add to his Grand Slam tally, has played a whopping total 77 matches this season. Cotorro believes the the high number aggravated Nadal's old knee injury.

The 31-year-old Rafael Nadal was a lock to finish the year World No. 1 after Roger Federer withdrew from the Paris Masters. Federer, after winning his eighth Swiss Indoors title, needed to put up a strong showing at Parris and the Nitto ATP Finals to challenge Nadal's throne. However, Federer cited a back injury and decided to forego his quest to finish World No. 1 for the first time since 2009. Nadal will finish a season atop the tennis world for the fourth time in his storied career -- after 2008, 2010 and 2013.