Birmingham co-owner David Sullivan has admitted that Blues are braced for a number of high-profile departures in January.
Steve Bruce's side have reignited their failing title bid in recent weeks, but when the transfer window opens the Midlands outfit are preparing to see both David Dunn and Matthew Upson leave St Andrews.
According to Sullivan, England international Upson has made clear his desire to return to The Premiership, with Portsmouth boss Harry Redknapp recently confirming his interest in the former Luton Town trainee.
Upson is also reportedly attracting interest from Newcastle United and Tottenham Hotspur after returning to training following an Achilles injury picked up in April, and with just 18 months left on the defender's contract Blues are ready to cash in in January.
Midfielder Dunn's contract runs out at the end of the season so Blues are also believed to be ready to listen to offers for the former Blackburn man, with Sullivan admitting that departures are likely in the new year.
"There will be some players leaving in January," Sullivan told The Mirror.
"Matthew Upson is a great player but he wants to go to a bigger club."