Socceroos coach Ange Postecoglou's decision to leave Illawarra veteran Luke Wilkshire out of the World Cup squad is in danger of spectacularly back-firing, after right back Ivan Franjic was ruled out of the tournament.

Stop gap option Ryan McGowan replaced Franjic in the 48th minute of Australia's thrilling 3-1 loss to Chile on Saturday morning and now faces a huge task as part of the team's defence against the might of Spain and the Netherlands.

With Australia's campaign teetering , Postecoglou conceded he could employ lateral thinking to cover the collateral damage of Franjic's absence.

Franjic tore his left hamstring in a 3-1 loss to Chile which Postecoglou says is sinking in.

"The disappointment becomes greater," he said in Vitoria on Saturday, a day after the defeat.

"After the game I thought it was an opportunity missed and that was further emphasised ... you have lost a game of football we felt we could have got something out of."

Wilkshire was the last man cut from the squad, missing out on a third World Cup appearance after travelling to Brazil.

He was expected to at the very least be a back-up option to Franjic as part of the squad, but Postecoglou rolled the dice with a young group instead of involving the Russian Premier League player, who played his junior years with the Wollongong Wolves and Albion Park.

Postecoglou said McGowan loomed as a ready replacement in Franjic's right-back slot, but he was considering other options.

"Ryan is a solution, there could be a couple of different things in the way we approach things," he said.

"Holland represents a different problem to Chile so we'll have a look in the next couple of days."

Australia face a red-hot Netherlands in Porto Allegre on Wednesday (Thursday AEST) after the Dutch thumped reigning champion Spain 5-1.

Postecoglou said losing Franjic was a "massive disappointment".

"I'll talk to him later, but there's not a lot you can say but what he has tasted should be motivation to come back for more."

Postecoglou was thoroughly reviewing Australia's loss to Chile and not prepared to label the defeat as gallant.

"I'm not one to be happy about brave defeats," he said.

"And it's a results-based business. We never said this World Cup was about anything other than results and we won't shy a way from that, even while taking a long-term view on many decisions.

"We went out to win a game of football, not damage limitation or give guys experience.

"Two-nil down after 15 minutes, if there was ever going to be an exercise in damage limitation it was then - but we didn't do that."

Postecoglou said he would seek tactical improvements, believing Chile's initial two goals in Cuiaba were preventable.