Borussia Dortmund left-back Marcel Schmelzer is likely to miss the big Bundesliga clash against leaders Bayern Munich after having yet to fully recover from a muscle injury.
The Germany international was injured in training prior to last week's friendly game against Ukraine.
"He has not trained with the team and time is running out," coach Jurgen Klopp told reporters ahead of Saturday's encounter in Munich.
Champions Dortmund have moved up to second place with five wins in the last six games and are five points behind Bayern.
VfL Wolfsburg forward Mario Mandzukic is doubtful for Saturday's league game against Hannover 96 with the Croat picking up a toe injury while on international duty.
"Unfortunately he returned from the national team with an inflammation in the toe and has been unable to train," said Wolfsburg coach Felix Magath.
"But the medical staff are hopeful that he could play on Saturday," added Magath, who on Thursday sent fellow striker Patrick Helmes to train with the reserves for the rest of the year.
Hannover have their own injury concerns with midfielder Sergio Pinto doubtful for the regional derby at Wolfsburg with a nagging ankle injury.
"It will be tight time-wise," Hannover coach Mirko Slomka told reporters. Europa League competitors Hannover are in sixth place on 19 points after a good start to the season.
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