Postecoglou takes charge from the sacked Nuno Espirito Santo three games into the new season.
The Daily Mail says the Australian addressed the squad on Wednesday, assuring them that everyone will have an equal chance of selection.
The likes of Omari Hutchinson and Douglas Luiz, who both arrived in the summer, had been largely overlooked by Nuno so far this term. It's been claimed Nuno made the call as he wasn't involved in either signing.
Postecoglou kicks off his time as Forest manager against Arsenal on Saturday.
He is also expected to only "tweak" the tactics of Nuno in the coming weeks, despite his commitment to a set system and style of play.
