Celtic midfielder Tom Rogic will be out for up to six weeks after sustaining a knee injury in the Asia Cup.
The Australian missed the Old Firm derby defeat by Rangers in December to play for his country in Dubai.
Manager Brendan Rodgers has confirmed the 26-year-old will undergo surgery to correct the issue.
"It is a real blow for us," Rodgers said. "He's seen a knee specialist in London, but we'll be without him for a while."
Rogic played five times for Australia squad during January but missed their quarter-final defeat by United Arab Emirates.
"He came back from the Asia Cup and had an issue with his hand out there and got inured with his knee when he landed awkwardly," Rodgers said.
"He went yesterday to check his hand didn't need an operation and, while he was there, we thought we would have his knee looked at and it showed up a lateral meniscus problem."
Celtic have won four games in a row in Rogic's absence and sit four points clear at the top of the Scottish Premiership, but Rodgers was keen to have the midfielder back in the side.
"He won't need the operation on his hand but needs it on his knee," the manager added. "Not what we expected but that's the way football works. It is unfortunate.
"He is a good character. It is disappointing for us. We have missed him for the period of time he has been out, the last month or so."