Celtic will be without the services of captain Scott Brown for up to three months.
The 30-year-old picked up a knee injury during the 0-0 draw with Kilmarnock at the weekend.
Having had the complaint assessed, manager Ronny Deila confirmed that the midfielder may not return to action until late February or early March.
"Scott Brown is out for a while. We don't know for sure yet but it could be eight to 12 weeks," he told reporters.
Deila made the revelation ahead of tomorrow's Europa League group encounter against Ajax at Parkhead.
