Celtic boss Tony Mowbray is coming to terms with his injury-ravaged squad after their Old Firm defeat at the weekend.
The Bhoys suffered a 2-1 defeat at Ibrox on Sunday after a brace from Kenny Miller was enough to take Rangers to within a point of the SPL league leaders.
Celtic, who pulled a goal back through an Aiden McGeady penalty, were already without Barry Robson, Marc-Antoine Fortune, Andreas Hinkel and Danny Fox for the Glasgow clash but have further injury woes after the subsequent defeat.
Scott Brown, Shaun Maloney and Stephen McManus have now been added to the list and the Scotland trio may all be forced to pull out of their national squad, who travel to Japan for a friendly this weekend.
"We've got to wait and see about that," Mowbray told the Evening Times. "There were a lot of players with ice on in the dressing room at Ibrox.
"Maloney has got an Achilles problem and obviously we know about Brown's ankle. McManus has got stitches and whether that's a problem for him or not, I don't know.
"All we can do is wait and see how they all are over the next few days."
Mowbray's mood will have been dampened further by the news that referee Craig Thomson admits he should have awarded Celtic a second penalty on Sunday.
With Rangers leading through Miller's eighth minute opener, Thomson ignored appeals for a spot-kick soon after when Maloney went down in the box after David Weir left a leg out.
Thomson did award the Hoops a penalty in the 25th minute after Rangers defender Sasa Papac tripped debutant Zheng Zhi and McGeady scored from the spot.
However, by then, Miller had grabbed his second and the Ibrox side ultimately held out for a morale-boosting win.
Through the Scottish Football Association's Head of Referee Development, Hugh Dallas, Thomson pled guilty to getting the Maloney decision wrong, but Mowbray holds no bitterness towards him.
"Taking charge of an Old Firm game is both high profile and challenging," Mowbray said.
"Referees are well aware that their performance will be judged on calling the major decisions correctly.
"Craig and I have had our post match de-brief.
"Whilst I would compliment Craig for his overall handling of yesterday's encounter, he is disappointed at his error of judgment when he decided against awarding a penalty to the visiting team in the 12th minute.
"Our referees are fitter than they have ever been and our referees are better prepared for matches than they have ever been.
"We are working each and every day with our top officials to make sure that they are in a position to get the big calls right.
"However, mistakes are part and parcel of football.
"I think that it says a lot for the character and professionalism of Craig that he has been more than willing to hold his hands up on this one."