The Wanderers confirmed the signing of the 25-year-old Australian on Tuesday, adding to an already strong defence.

Captain Michael Beauchamp and Nikolai Topor-Stanley were arguably the A-League's best central defensive pairing last season.

Popovic is unsure what condition Spiranovic is in just over a week out from the start of the season and said he was yet to consider changing from the style – or 4-2-3-1 formation – which Wanderers used on their way to winning the Premiership and losing the grand final last campaign.

"Not at the moment. I haven't thought of that," Popovic said when asked if he had considered changing to accommodate his three strong central defenders.

"We've got to first see where Matt's at in terms of his fitness and condition. It's great to have flexibility.

"We want to have a strong squad and we want to get better and we feel that all of our additions make us a better squad and Matt does that also."

Popovic said to expect more of the same from the Wanderers this season, but wants all-round improvement from his side.

"I don't think we really need to do anything different, I think we need to do it better," he said.

"The way we play, we need to improve the way we play. Within our structure, we need to do it better. That's been our focus in pre-season and will continue throughout the year."

Preparing for both the A-League season and the AFC Champions League, Popovic talked up the depth and quality Spiranovic would add to his squad.

Popovic said he and Spiranovic were both confident playing in the A-League would improve his chances of making Holger Osieck's Socceroos squad for the 2014 World Cup.

"He's confident they will. We're confident as well that we can help him," Popovic said.

"We've got to help him to be the best he can be and then the decision is up to Holger.

"They've got to be at their best and that's all they can do. If they control what they control, the rest is out of their hands."