Nadal's return doubtful as he cancels training camp

World number one Rafael Nadal's return to competitive action has come under serious doubt after he was pulled out of a five-day training camp in Mallorca this week.

Last month, Nadal had announced the withdrawal from the ATP finals citing a knee injury after he was defeated by Belgium's first-time qualifier David Goffin in the opening match.

The injury had also forced him out of Paris Masters, which took place in November.

Though Nadal had expressed confidence of being fit in time for the season-opening Australian Open, his participation now remains under the cloud after the Spaniard cancelled the planned training camp with training partner Joao Sousa.

Meanwhile, Sousa confirmed that Nadal is still not ready to practice due to the injury.

"He called me to tell me he was not feeling well," Sport24 quoted Sousa, as saying.

Sousa further confirmed that the world number one had recently travelled to Barcelona for another check-up on his troublesome knee.

Nadal is slated to make a comeback at the Mubadala World Tennis Championship in Abu Dhabi, beginning December 29.