Postecoglou has taken over from Frank Farina and will let Rado Vidosic take charge.
He said: ''Me arriving this late, it would be ridiculous to take over and disrupt things.
''Although I was super keen to get out there once the players started training.
''I have only really had 12 months out of the game as a coach while working in the media [at Fox Sports after coaching Australian youth teams from 2000-2007]. And you miss it. Certainly coming here today watching the players train, I can't wait to get started. But wiser heads prevailed and told me just to sit out tomorrow.''