Niko Kovac has conceded Bayern Munich "have a very bad feeling" over Niklas Sule's condition after the defender sustained an injury in the Bundesliga draw with Augsburg.
With Bayern 1-0 down to Alfred Finnbogason's first-minute opener, Sule went down clutching his left leg after going into a challenge with Florian Niederlechner.
After receiving treatment, Sule did manage to walk off the pitch, though it is feared the 24-year-old Germany international may have sustained cruciate ligament damage.
Kovac confirmed the news was not good, though Bayern's coach still harboured some hope the ligaments had not sustained serious damage.
"It looks like he's seriously injured, so we'll have to wait for the scans, but have a very bad feeling," Kovac told a news conference.
"We hope the cruciate ligaments are spared, otherwise we would miss Niki for a while.
"The general feeling isn't good. We need to wait and see what has happened and hope for the best."
Sule, who has been one of Bayern's most consistent performers since Kovac took over, had started 12 matches in all competitions this term.