Birmingham boss Steve Bruce is hoping to convince Matt Upson to stay at the club.
The player's agent revealed on Sunday that Upson was likely to leave St Andrews after turning down a new deal.
Upson's current contract expires in the summer and a number of Premiership clubs are thought to be lining up a move for the England international in the January transfer window.
However, Bruce is refusing to give up hope of keeping Upson, saying he wants to build his side around the former Arsenal man.
"I've got to be strong enough and we've got to be strong enough about Matt now the transfer window is open," said Bruce.
"Matt Upson could be the key to getting us to where we want to be - he's a very, very good player.
"If the situation stays the same by the summer and hopefully we are in the Premier League, then we can re-address it - we can make him an offer he can't refuse.
"I have said to Matt that if we get back up, then we would want to build our team around him.
"Of course, he is looking at the situation. He is devastated with the injuries he's had and also he's devastated that he's not playing in the top league but that could all change in three or four months.
"Where can I go and get an England centre-back, who is left-sided and 27 years old with his quality? I don't think I can.''