Neil Lennon hopes Celtic are able to sign a defender to ease his injury concerns in that area.
Thomas Rogne went off injured in the 4-1 win over Aberdeen on Saturday, leaving the Hoops boss short of options ahead of Tuesday's match.
Glenn Loovens and Daniel Majstorovic are both out injured, while both Darren O'Dea and Jos Hooiveld are out on loan.
Lennon now hopes chief executive Peter Lawwell finds the funds to bring in much-needed reinforcements.
"He (Rogne) was feeling his calf," Lennon said. "He may have a calf strain so we'll see how he is tomorrow.
"The club have been pretty diligent in trying to get a centre-half in. That will just reinforce their efforts to get one in who we have identified.
"We hope we can cross the line."
He added: "I'm not (optimistic), there are no guarantees about anything at this stage of the season.
"Clubs want to hang on to their players because they are either going for promotion or trying to avoid relegation or win trophies, so it's difficult."