Celtic defender Mikael Lustig faces four months on the sidelines after undergoing a double hip operation.
Manager Neil Lennon revealed the Sweden right-back had been playing through the pain barrier for several months.
With his country failing to reach the World Cup finals and Celtic out of the Champions League, the decision was taken to undergo surgery.
The 27-year-old has been in impressive form for Celtic but Lennon revealed he had been hampered by the problem.
Lennon said: "Lustig had surgery, four months. He had both hips done, so the procedure was a bit more in-depth than first thought.
"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."