Cologne will be without defender Pedro Geromel for three weeks after sustaining a thigh injury.
The 24-year-old has damaged adductor muscles and is now unlikely to be available for selection until the end of March.
Cologne manager Frank Schaefer has admitted that the loss of Geromel is a setback for his mid-table Bundesliga side.
Schaefer told his club's official website: "It is certainly a blow for us."
Geromel has been a first-team regular with Cologne since joining two years ago and he is under contract until the summer of 2014.