Rafa Nadal
Rafael Nadal has been hit by injuries in recent months Getty

Rafael Nadal has pulled out of next week's ATP Paris Masters for "personal reasons", adding fuel to the speculation surrounding his participation in the ATP World Tour Finals in London next month.

The Spaniard was diagnosed with appendicitis on Sunday 5 October and even though he has since played the Shanghai Masters and is currently at the Swiss Indoors in Basle, his participation in the Paris Masters as well as the season-ending World Tour Finals in London next month has been cast in serious doubt.

The French Tennis Federation (FFT) has confirmed he will not play the Paris Masters due to "personal reasons", being automatically replaced in the draw by his compatriot Pablo Andujar.

The 28-year-old Spanish star is currently preparing for his quarter-final against Borna Coric at Basle but he recently revealed he is dealing with the appendicitis with antibiotics and will require surgery at some point.

Even though the World No 3 is yet to explain the reasons, there is speculation that he may undergo the surgery just after the Swiss tournament.

US Open champion Marin Cilic and Gulbis have also withdrawn because of injury, being replaced by Pole Jerzy Janowicz, a finalist in 2012, and Canadian Vasek Pospisil.