Birmingham may be forced to sell Jack Butland in January to keep the club out of administration.
The 19-year-old England goalkeeper is wanted by several teams and Liverpool are understood to have already held talks.
Blues rejected a £6m bid from Southampton for Butland in the summer, but acting chairman Peter Pannu has admitted the cash-strapped club may not be able to resist such temptations next month.
"Give me a £15m offer for Jack Butland, can I say no?" said Pannu. "I have rejected £6m from Southampton (in the summer) but I rejected it when finances were OK. I might not be able to reject it if I get something similar.
"I do have a responsibility to keep the club running."
Nikola Zigic, 32, is another high earner who could leave – his £50,000 plus-a-week wages are also a threat to the Blues' finances.
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