The Spaniard withdrew from the season-ending ATP World Tour Finals in
November after losing to David Goffin, citing a knee injury that had
also forced him out of November’s Paris Masters.
Nadal appeared confident of being fit in time for the Australian Open
in January, but that now longer seems to be a certainty after he pulled
out of a planned training camp in Mallorca this week with training
partner Joao Sousa.
Portuguese journalist Jose Morgado quoted Sousa as saying Nadal "still isn't ready" to practice.
“He called me to tell me he was not feeling well,” Sousa said.
Morgado also revealed that Nadal travelled to Barcelona on Monday for another check-up on his troublesome knee.
The 31-year-old is scheduled to play in the exhibition Mubadala World Tennis Championship, which starts on December 29.