Christopher Jullien will be out for up to four months with a knee injury, Celtic manager Neil Lennon has revealed.
The 26-year-old French defender crashed into a post while making a clearance during Wednesday's 3-0 win over Dundee United at Parkhead and was taken off the pitch on a stretcher.
Ahead of the Old Firm game against Rangers at Ibrox, Lennon told Sky Sports: "He is a very important player for us.
"But it is a bad injury, we are to lose him for a period of time, maybe three or four months.
"On the eve of this game it is a hammer blow for us really."