Celtic manager Ronny Deila insists he has no plans to sell any of his players in January.
Former boss Neil Lennon, now at Bolton, has confirmed his interest in Kris Commons, whose contract is up at the end of the season.
And defender Virgil van Dijk has been linked with a move to England.
"I have said that all the time, we want to keep all our best players," said Deila. "To get someone out of Celtic now is going to be very hard."
Earlier this month, Commons' agent said the 31-year-old midfielder was no nearer agreeing a new deal.
Martin Reilly wants a two-year deal for his client and an upbeat Deila stressed that remains negotiable.
"Yes, there is a chance for that," said the Norwegian. "But you have demands from the club and demands from the player and you have to meet each other with a good deal for both."
And he shrugged off the possibility of an approach from Bolton for last season's PFA Scotland Player of the Year.
"Nothing worries me," added Deila, who hopes to sign Dundee United winger Gary Mackay-Steven on a pre-contract deal. "To be at Celtic is fantastic.
"The players who are here have to want to be here and Kris wants to be here.
"Kris showed in the game last week against Kilmarnock that he can be in a Celtic team that I coach. He has been in the team so many times this year.
"If he plays the way he did last week he is going to been an important player for us.
"He will stay here until the end of the season. Virgil van Dijk is also staying. We want to strengthen the squad."