Warburton was sacked by Forest on New Year's Eve - less than eight months after he kept them in the Championship on the season's final day.
But the 55-year-old could be poised for a return with Bradford, who parted company with Simon Grayson last week.
Warburton began the week far adrift of the leading bookies contenders, but soon emerged as the 3/1 front runner before seeing his odds shortened further - creating daylight between himself and another former Nottingham Forest manager, Steve Cotterill (3/1).
A former City trader, Warburton's managerial CV contains two promotions - including one out of League One with Brentford.
The Londoner subsequently led the Bees to the Championship play-offs before a mixed spell at Rangers.
Ian Cathro (8/1), Uwe Rosler (8/1), Grant McCann (9/1) and Hannes Wolf (10/1) are also in the Sky Bet mix.
Would the former Rangers and Nottingham Forest boss be a good appointment for Bradford?