Postecoglou made it clear at the press conference which accompanied his squad announcement that he sees Mat Ryan as the standout candidate to inherit the gloves, ranking him above Borussia Dortmund's Mitch Langerak in the pecking order on the grounds the former Central Coast Mariner is receiving regular game-time (and winning rave reviews) at Club Brugge. Liverpool's Brad Jones is there to make up the numbers.
Expect Ivan Franjic and Jason Davidson to keep their spots from the Costa Rica friendly at right and left fullback respectively, with Luke Wilkshire recalled to provide cover.
Postecoglou said he knows Ryan McGowan intimately, so perhaps he will opt to partner Matthew Spiranovic with Curtis Good at centre-back. Chris Herd can also play across the backline, but the Aston Villa fringe player is in the squad primarily for the coach to have a closer look at him and may not get on the pitch.
Swindon Town youngster Massimo Luongo is the biggest unknown factor in the squad and it would be disappointing not to see the former Tottenham Hotspur player get minutes. Where he is deployed remains to be seen. Mark Milligan and Mile Jedinak started and performed strongly in holding midfield roles against Costa Rica, with James Holland pushing for one of those two spots. Milligan is able to play at centre-back, but Postecoglou would surely be reluctant to lose his energy and passing range from the midfield.
Matt McKay is another central midfielder and the Brisbane man can also play wide and in defence. We're not sure what Postecoglou can learn from having his former Roar skipper in the squad, but he made a point of saying he had only called up A-League players for the long flight to London if he intends to use them. That being said, Postecoglou would surely prefer an opportunity to see what Adam Sarota can do in green and gold.
Tom Rogic, if deemed fit enough after picking up an ankle problem last month, should occupy the central attacking midfield role, with Tommy Oar the incumbent on the left. According to Postecoglou, any of Mathew Leckie, Oliver Bozanic or Dario Vidosic could step in for the injured Robbie Kruse on the right flank. Ben Halloran was also among the candidates until his withdrawal from the squad due to injury. Brett Holman has been called up in his place.
If Leckie doesn't start out wide he will be competing with Tim Cahill for the centre-forward's role. In the absence of Lucas Neill, the New York Red Bulls man could captain the team if he starts, with Milligan and Jedinak the other leading candidates.