The 33-year-old could leave the club at the end of the season when his contract runs out.
Chairman Julian Rhodes told the Telegraph and Argus:``We are in discussion with Nicky and his agent about extending his contract for a year. It has been going on for the past few weeks but nothing is sorted yet.''
The former Leicester and Manchester City player, who scored against Sheffield Wednesday last weekend, has been with the Bantams since 2003.