Scott Brown is facing a second ankle operation and could be out of action for the remainder of the month.
The midfielder is due to return to see a London specialist this week about the injury that has dogged his season.
Despite a summer ankle operation Brown returned to the specialist last month with Tony Mowbray admitting that another visit, and possible operation, is scheduled.
The Celtic boss said: “I am now resigned to not having Scott available for the next few weeks. His problem has not gone away, and every time he gets a heavy challenge on his ankle, we are back to square one.
“As I have always said, the bottom line has to be the player’s welfare, and we will leave it in the hands of the experts.
“Whether Scott needs a small operation, further injections or simply time away from matches, they will decide.
“The important thing is having him fit for the long term. We don’t want to be in a situation where we play him for a few games and then have to rest him for a few.
“That has been the case this time. But to be fair to ourselves, he said he felt absolutely fine after his last trip to the specialist.It is very frustrating for us all.”
Brown has played 13 times for Celtic this season plus three games for Scotland but has failed to recapture the form of last season.
