Bayern Munich boss Carlo Ancelotti reportedly fears the worst after seeing goalkeeper Manuel Neuer pick up another injury during a training session on Monday.
The Germany international, who spent time on the sidelines with a hairline fracture in March, is said to have broken his foot in a recurrence of the long-standing problem.
According to German publication Bild, the 31-year-old is facing another lengthy spell on the sidelines as a result of the damage sustained at the club's Sabener Strasse training base.
Neuer has already been ruled out of Tuesday night's Bundesliga meeting against Schalke, with further tests expected to reveal the full extent of the damage in the coming days.
Former Stuttgart stopper Sven Ulreich and academy product Christian Fruchtl are Ancelotti's back-up keepers.
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