Pedro Geromel is facing a lengthy lay-off after sustaining a serious knee injury during Cologne's weekend victory.
Reports suggest the skipper could be out of action until the New Year after tearing the meniscus in his right knee.
The 26-year-old Brazilian-born Italian was injured in the club's 4-1 Bundesliga victory at Bayer Leverkusen in the Rhine derby on Saturday after a collision with Stefan Kiessling in the closing minutes of the game.
The former Chaves and Vitoria Guimaraes central defender underwent surgery on Monday to rectify the problem.
Head coach Stale Solbakken told Kicker-Sportmagazin: "We have to try to deal with this situation right now.
"We have to make two or three changes and this is always a problem for every team."
He sarcastically added: "I reckon you should come over to our place if you're a defender and if you're unattached at the moment. You would have a great chance to earn a contract with us."