Manager Brendan Rodgers has claimed that he is unaware of reports which have suggested that Tom Rogic has rejected a new contract.
Rogic still has just under 18 months remaining on his existing deal, but Celtic are keen for the 25-year-old to commit his future to the club after scoring 24 goals from 120 appearances in all competitions.
Rodgers has acknowledged that the two parties have been locked in negotiations, but the Bhoys boss has said that he has not been informed of any developments on the matter.
The Northern Irishman told Sky Sports News: "I am not aware of that to be honest. We have just arrived back from Russia. I know Tom and his representatives have been speaking with the club for a little bit of time but that is the first I have heard about that."
The 45-year-old added: "Tom is a very important player for Celtic. He has been a joy to work with in my time here. He has been here for a considerable period of time but certainly in the 20 months I have been here he has been absolutely brilliant.
"Of course, at Celtic we want to keep our best players. It is not always easy because at times they will either want to move on or offers come in from clubs."
Celtic currently sit nine points clear at the top of the Scottish Premiership table.