With first-team coach Paul Williams named as caretaker until the end of the current season, the odds from Sky Bet are for who will be in charge of the Reds on the opening day of the 2016/17 campaign.
Nigel Pearson is the favourite but odds of 5/1 show how wide open the field is, with no standout candidate.
Williams is a 10/1 shot while former Forest managers Alex McLeish and Billy Davies are also in the betting.