The 67-year-old, who played for the Millers between 1969-71, looks set to answer the club's SOS and take the job until the end of the season.
The Millers are looking to for a candidate to take the job on a short-term basis with the sole ambition of keeping them in the Championship.
A last-gasp defeat to Bolton on Saturday has seen them bin their long-term vision which had Neil Redfearn as the man to end an inherent short-termist approach at the club and provide a sustainability with the development of younger players.
Redfearn and the club's new plan lasted four months and 21 games.
Although personal terms and in-depth discussions are not yet believed to have taken place, the club are reported to be "down the line" with the appointment and Warnock is known to be open to the role.
The short-term nature of the job, which could come with a hefty bonus if survival is achieved, would suit the former Sheffield United, Crystal Palace, QPR and Leeds manager, who lives in Cornwall.
An appointment could happen before Saturday's game with Birmingham, though Nicky Eaden has been placed in caretaker charge just five days after joining the club as Redfearn's assistant.
