The new head coach of the national team is waiting for one of several promising young shot-stoppers to prove they have what it takes to replace the retired great
Schwarzer's decision to retire from international football on Wednesday has opened the door for a host of gloveman to vie for the Socceroos' number one jersey ahead of next year's World Cup.
Borussia Dortmund's Mitch Langerak and Mat Ryan of Club Brugge have been given first crack at the role after being included in the 22-man squad for the upcoming friendly with Costa Rica.
Adelaide United skipper Eugene Galekovic, Reading's Adam Federici and Liverpool's back-up Brad Jones are also likely to be in the frame for selection.
"There's an opportunity there for everyone," Postecoglou said on Wednesday.
"Both Mitch Langerak and Maty Ryan are exceptional young goalkeepers ... I'm very keen to get them both in.
"The goalkeeping position is a very important, highlighted by looking at the impact Mark Schwarzer has had on our national team.
"There's an opportunity there for them but not just them. They get first crack at it but Euguene Galekovic has had a fantastic start to the season and he's a keeper I rate highly.
"At the moment all I'm offering people is an opportunity and those two get that opportunity and it's up to who takes it."
Postecoglou paid tribute to Schwarzer's influence on the Socceroos squad over the last decade in particular and denied the 41-year-old was pushed into hanging up his gloves.
Asked if he had spoken with Schwarzer and possibly hinted he wouldn't be part of the World Cup plans, Postecoglou said: "I haven't had a conversation (with Mark).
"So everything after that is irrelevant. Mark was picked in the (Costa Rica) squad but last night he informed us he was retiring.
"We respected that decision and we move forward. It was his decision.
"He's no doubt one of the all-time greats for the Socceroos, was always available to play for his national team and sometimes under difficult circumstances.
"He's an absolute icon of our game and will rightly be acknowledged by everyone at the appropriate time."
The main focus for the Socceroos' new coach now is on learning which players will fit into his plans heading to the World Cup and beyond.
After recent 6-0 defeats to both Brazil and France, followed by a 3-0 win against minnows Canada, Postecoglou also hopes the Costa Rica game can be the next step on the road to recovery for the team and their fans.
"We want to give everyone in the country belief that we can go to the World Cup and give a good account of ourselves," he said.
"My main focus will be the players. We've been through a tough time and a difficult time and I'm hoping when they run out against Costa Rica in front of a packed stadium we can restore some confidence to them and give them some belief that we can achieve great things.
"I'm pretty bullish that we don't talk down our national team. I'm not afraid of stumbling along the way and I won't be downplaying our chances and I want our players to be the same way.
"Hopefully at the end of the game we've restored some of that confidence and belief and get them feeling good about the World Cup campaign and where we're heading."