Grayson is fourth favourite for the Aston Villa job with some bookmakers, having led Preston to 11th this season.
However, the report claims the 46-year-old is unhappy at a prospect of a review, casting doubts over his future.
Aston Villa, where Grayson spent two years as a player, are said to be "keeping tabs" as they prepare for life in the second tier.
And Grayson is the fourth favourite with most bookmakers to take the Villa Park post, which has been vacant for over a month.
The Yorkshireman has an impressive managerial CV, having won promotions - albeit from the third tier - with all four of his clubs, Blackpool, Leeds United, Huddersfield Town and Preston.
And with Villa owner Randy Lerner looking to sell up, an unattached Grayson is likely to appeal from a financial point of view too.
Another free agent, Nigel Pearson, remains the front-runner with the bookies - ahead of Championship bosses Steve Bruce and Mick McCarthy.