Mills is one of the highest earners at Leeds following his £4m move from Charlton, but he could be allowed to leave as the club look to reduce their stifling wage bill.
Leeds boss Peter Reid is reluctant to sell any more star players from a squad that has been decimated over the past two seasons though he is willing to make an exception for Mills.
Mills appears to have fallen out big-time with Peter Reid and he may well move the England full-back on to generate some funds for a late move into the market, before the transfer window closes Sunday week.
Leeds would be happy to listen to offers, and a fee of around £2m has been banded around.
City, though, are unlikely to be the only interested party for a player who earned his 18th cap as a substitute last night against Croatia.
Wolves have admitted they had an interest in the summer, but took it no further, whilst Birmingham, Blackburn, Arsenal and Middlesborough have all been linked with the England full back in recent days