James Forrest will be out for "quite a considerable time" after having ankle surgery on Tuesday, says Celtic manager Neil Lennon.
The Scotland winger, 29, has been absent since late September, sitting out eight matches for his club so far.
He also missed three internationals and will not be involved in next week's Euro 2021 play-off final in Serbia.
"Best-case scenario, we're probably looking at six-to-eight weeks. It may be longer than that," said Lennon.
"We'll just need to see how he settles after the surgery. We think it's been a success."
Team-mate Mikey Johnston recently had an operation on a knee injury and has returned to training, while Christopher Jullien, who has been missing with a back problem, will rejoin his team-mates soon.
"He's going to be a while yet, he's still feeling the effects of the surgery," Lennon said of Johnston.
"Christopher we're hoping will be back in the country tomorrow and resume training not so long after that. You probably won't see him until after the international break's over."
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