The 30-year-old is out-of-contract and recently saw a move to Bolton Wanderers collapse.
West Bromwich Albion have also expressed interest, though Leeds boss Kevin Blackwell is hopeful of persuading him to drop into the Coca Cola Championship this season.
The Whites have already purchased centre backs Clarke Carlisle and Paul Butler and still have Michael Duberry, Lucas Radebe, Matthew Kilgallon and Dominic Matteo in the squad.