Celtic manager Brendan Rodgers has confirmed Tom Rogic needs surgery on a knee injury and will be out of action for up to six weeks.
The Australia international has yet to play for Celtic in 2019 as he was on duty for his country at the Asian Cup, where Graham Arnold's side lost to United Arab Emirates in the quarter-final.
And Scottish champions Celtic will now be without Rogic for another spell as he requires an operation.
"Tom is actually going to be out for six weeks which is a real blow for us," Rodgers told reporters ahead of Sunday's trip to St Johnstone.
"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.
"He went down to London with a member of our medical team yesterday to check that 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 that a lateral meniscus problem, which is going to put him out for up to six weeks.
"Not what we expected but that's the way football works. It is unfortunate. He won't need the operation on his hand but needs it on his knee. 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, to have him out for another six weeks is a blow."
Celtic are top of the Scottish Premiership with a six-point cushion from rivals Rangers.
Rogic has made 15 appearances for Rodgers' side in the league, scoring three goals.
