Celtic defenders Mikael Lustig and Jozo Simunovic have reportedly sustained injuries which could keep them out of the Champions League games with Bayern Munich.
After earning a 3-0 win away at Anderlecht, Celtic have put themselves in a position where they are currently considered as direct rivals to Bayern for second position in Group B.
However, there are doubts over whether either Lustig or Simunovic will be able to take their place at the back after sustaining fitness issues while on international duty.
According to Afdonbladet, Lustig may be forced to sit out their fixtures with Luxembourg and the Netherlands after picking up a knock in training.
The governing body for Bosnia and Herzegovina have also revealed that centre-back Simunovic has suffered a torn hamstring and is definitely out of their matches with Belgium and Estonia.
Celtic travel to Germany to play Bayern on October 18, before the reverse fixture takes place in Glasgow on October 31.