The 34-year-old has played a major role in Birmingham's Carling Cup success.
It is being claimed that Fulham boss Mark Hughes is keen on the defender, who will have a year left on his contract in the summer, and he could be set to test Birmingham's resolve once the transfer window reopens.
If Hughes does make a bid for the veteran right-back, who will be 35 in August, he can expect competition from Stoke boss Tony Pulis.