Cluj star Bilel Omrani could miss this week's Europa League clash and his strike partner Lacina Traore is also set to sit it out.
Omrani was carried off after being crocked on Sunday night and the Hoops face the Romanians on Thursday desperate for revenge following their 4-3 shock home loss in the Champions League qualifier in August.
Omrani proved to be Celtic's downfall that night by netting two crucial goals, including a penalty as Dan Petrescus men inflicted Neil Lennon's men's only defeat so far this season.
But he's a major doubt now for the game after being injured during their 3-0 win against Gaz Metan, after the French striker scored his seventh goal of the season.
Ivory Coast international hitman Traore was also injured and both are touch and go for the game in Glasgow, leaving Petrescu with a major injust crisis.
Cluj No.2, Alim Minteuan, standing in for the suspended Petrescu said: "We will know later this week after they have done tests, but it's not looking good just now."
And Cluj star Ciprian Deac reckons Celtic's won't make the same mistake twice of underestimating Cluj after that third qualifying round shocker.
He said: "I know Celtic will treat us far mire seriously now that they did in the first two matches we played against them this season.
"We expect an even tougher game because Celtic will be out for revenge.
"Even if we do have a couple of injuries, we have shown before we can cope with it.
"We are going to Glasgow to try and win again. Why not? We've already proved we can beat them and we also defeated Lazio so there is absolutely nothing to be afraid of."
