Australia's coach has made five changes to the group of players picked for the 0-0 draw with the United Arab Emirates and 1-0 loss to Qatar last month.
Midfielders Matt McKay, Mitch Nichols, Terry Antonis and Aaron Mooy are all in for the international friendly against Japan on November 18, while Adam Federici, Bernie Ibini, Tomi Juric, Brad Smith and Tommy Oar make way.
The Socceroos are yet to convince following their encouraging performances at the World Cup, prompting concerns over their capacity to compete on home soil at the Asian Cup in January.
But the former Brisbane Roar and Melbourne Victory boss refuted suggestions he might prefer to have settled on a regular squad going into a major tournament.
"You've got to deal with realities," he said.
"The realities are that we need to expand our playing pool. It's as simple as that. You can't just manufacture that over night.
"Should our national team ever be settled? As I've said from day one, I don't feel that anyone should think that being part of the national team is guaranteed. I don't want to be caught short by injuries on the eve of the Asian Cup. From that point of view, everything we've been doing has been working exactly as I want it."
While Sydney FC's Antonis has been in excellent form early in 2014-15, the inclusion of Mooy and Nichols - another two midfielders - are perhaps something of a surprise, especially with the Socceroos' major recent deficiencies appearing to be a lack of goals.
Nevertheless, Postecoglou believes the form shown by the trio of young, domestic-based midfielders deserves to be recognised.
"We're still trying to broaden our playing pool," he said.
"We want to play a certain style of football and are looking for footballers who will fit in to that. I've been really impressed with the A-League the first few weeks (of the season), I think the standard's gone up another level.
"I've known Mitch for a very long time, I think he has some of the attributes that'll fit in to our style of play. Whether that can happen at international level will be his test. The same with young Aaron. I think he's had a solid start to his season at Melbourne City and again, has some of the attributes we're looking for, for the game we want to play."
Postecoglou offered an assurance that Western Sydney Wanderers centre-back Matthew Spiranovic and his club colleague, striker Tomi Juric, both of whom have battled injuries in recent months, remain strong candidates to feature at the Asian Cup.
"A guy like Matthew Spiranovic or even Tomi Juric, I had a good chat with Popa (Wanderers coach Tony Popovic) and it makes sense to leave them here and play games, because they need games. Would Matthew Spiranovic be in this squad if he was fully fit? Absolutely, he was our best defender at the World Cup."
Australia go into camp next Monday for the Japan friendly in Osaka, giving Postecoglou close to a full week to work with his players.
