Celtic boss Tony Mowbray has confirmed that midfielders Scott Brown and Shaun Maloney will both be out for another two months.
Brown had an operation on an ankle injury in the summer which failed to clear the problem and after being out for the last five weeks, he will have further surgery in Amsterdam next week.
Maloney's Achilles injury has kept him sidelined since the 1-0 defeat by Hearts in the Co-operative Insurance Cup in October.
Mowbray said: "Scott has been to Amsterdam to see a specialist.
"We have come to the conclusion where we go now.
"Scott will have a minor procedure in Amsterdam which will hopefully clear up his problem. Ultimately we need to get it sorted."
He added: "The specialist who is overseeing Scott is looking at him being out for six to eight weeks. Maloney is also out for the same length of time. There will be no surgery, just a course of injections.
"He has played with discomfort and he needs to sort it out now."
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