Bayern Munich manager Jupp Heynckes does not know when forward Arjen Robben will return to training following groin surgery.
The Dutchman underwent an operation at the beginning of October after aggravating an injury which has seen him make just four Bundesliga appearances this season.
And while Robben, who has been plagued by injuries in his career, is in the rehabilitation process, no date has been set for him to resume first-team training.
"Things are going relatively well for him," said Heynckes. "He has started the rehabilitation phase and is building up muscle.
"We are confident, but I can't say when he will train with the team again."
Robben is a major loss for Bayern, but they have been coping comfortably without the former Chelsea man to sit top of the Bundesliga and lead the way UEFA Champions League Group A.
Meanwhile, ahead of facing second division Ingolstadt 04 in the German Cup on Wednesday, Heynckes has poured cold water on speculation Takashi Usami or David Alaba could leave Bayern on loan.
"Our squad is not so big that we can afford the luxury of loaning out players," he said.