Grayson is 1/2 favourite to replace sacked Dave Hockaday with the early favourite Rolando Maran now 16/1 with bookmakers SkyBet.
The current Preston boss had a three-and-a half-year stay at Elland Road during his first tenure, leading the club to promotion from League One.
He also led Leeds to a famous 1-0 win against Manchester United in the FA Cup at Old Trafford. In Leeds first season back in the championship, he led the club to a seventh place finish.
Grayson was eventually fired in February 2012 despite Leeds being in the top ten in the championship, leaving with a record of 84 wins, 40 draws and 45 defeats in his 169 games in charge.
He has tasted promotion with Huddersfield Town and Blackpool and guided Preston into the play-offs last season. Preston are so far unbeaten in the league this term.
Others on the list include former West Brom boss Steve Clarkewith caretaker coach Neil Redfearn the third favourite
Former Leeds defender Neil Aspin, who is now in charge at conference side FC Halifax as seen his odds slashed from 50/1 to 16/1.