Bradford boss Peter Taylor has put club skipper Zesh Rehman on the transfer list "due to a club disciplinary matter".
Rehman, 27, has found a starting place difficult to come by this season and is understood to have infuriated Taylor by publicly questioning the manager's team selection policy.
A club statement read: "Bradford City would like to inform all clubs that Zesh Rehman has been placed on the transfer list.
"The defender will be available on a free transfer when the transfer window re-opens at the start of January 2011. This decision has been taken due to a club disciplinary matter.
"Any interested clubs are respectfully asked to contact the football club rather than speaking with the player direct. The football club would also like to inform supporters that they have decided to strip Zesh of the club captaincy and instead hand the role to Lee Bullock."
Pakistan international Rehman was the first British Asian to play in the Premier League when he made his debut for Fulham at Liverpool in 2004. He made 30 appearances for the Cottagers before moving on to QPR in 2006 and has had loan spells at Brighton (twice), Norwich, Blackpool and Bradford, signing a permanent deal at Valley Parade in July 2009.