Celtic defender Mikael Lustig has undergone a double hip operation and will be out of action for four months, manager Neil Lennon said on Friday.
Lennon said the Swedish right-back had been playing through the pain barrier for several months.
But with Sweden failing to reach the World Cup finals and Celtic being eliminated from the Champions League, the decision was taken to have a medical operation.
The 27-year-old Lustig had been in impressive form for Celtic but Lennon revealed he had been struggling to cope with the injury.
"Lustig had surgery, four months. He had both hips done, so the procedure was a bit more in-depth than first thought," the manager said.
"We are hoping he will be back March/April time but he had a lot of work done which makes his recent performances even more remarkable.
"His movement was restricted and he was in a lot of pain after games so it needed doing. So hopefully he will come back an even better player which will be brilliant for us."