WHICH FOUR AT THE BACK?

Ange Postecoglou's gutsy decision to switch to three at the back in the middle of World Cup qualifying saw him hounded by critics. New coach Bert Van Marwijk, said to be more pragmatic, is expected to reinstate a four-man defence. But who will be part of it? Trent Sainsbury is a lock, while Aziz Behich looks far and away the country's best left-back. However, right fullback is up for grabs and the likes of Matthew Jurman, Milos Degenek and uncapped newcomer Aleksandar Susnjar will jostle in an intriguing battle for the other central defensive role.

VETERANS IN THE WINGS

Australia's biggest star and its spiritual leader are both in need of minutes. Tim Cahill's A-League exit and arrival at Millwall has left him well short of match fitness but he appears to be in van Marwijk's plans - for now, at least. Mile Jedinak was the centrepiece of Ange Postecoglou's team and there's no reason he won't be under the Dutchman, but he'd be well served by more football at Aston Villa, where he's been in and out of the team with various niggles.

GERMAN EFFICIENCY

If Australia is to make an impact at the World Cup, German influence could be key. Livewire Robbie Kruse, based in Bochum, is one of the Socceroos' few X-factor players. So too Hertha Berlin's Mat Leckie, who has lost his No.1 supporter in Postecoglou but has established himself as part of the side's DNA and could play further up the park under the new boss. Then there's Brandon Borrello, who has starred for second-tier Kaiserslautern since leaving Brisbane Roar but was a surprising omission in van Marwijk's first squad. Can he break into the picture closer to the World Cup?

ON THE MOVE

Andrew Nabbout's stunning form has won him a transfer to Urawa Red Diamonds - will it also take him to Russia? The move is a risk if he can't maintain his new form in Japan, but van Marwijk clearly likes what he sees after selecting him for the March friendlies. Likewise, Mark Milligan (Al Ahli, Saudi Arabia), Trent Sainsbury (Grasshoppers, Switzerland) and Jamie Maclaren (Hibernian, Scotland) all have new homes that should bolster their hopes of making the final 23.

THE ARZANI DILEMMA

Does van Marwijk, on a six-month deal, have an eye to the future? Or will he simply make decisions that will enhance the team for the time he's part of it? How the Dutchman handles Daniel Arzani will provide the answer. The Melbourne City teenage sensation has lit up the A-League since being handed his first-team chance and Australia rarely produced players of his ilk. But he was overlooked for the friendly clashes against Norway and Colombia, potentially leaving the door ajar for Iran, the country of his heritage, to start courting him. Will Bert bite the bullet and give him a seat on the plane?

GOALKEEPING GLUT

Nowhere on the pitch has Australia been better served in the last 20 years than between the sticks. And so it is again in the lead-up to Russia. Mat Ryan is impressing in the English Premier League, Danny Vukovic is enjoying a late-career boom in Belgium and Mitch Langerak is first choice once more in Japan. Most intriguingly, Brad Jones is also officially on the radar with the change in manager and thoroughly deserving on the back of his title-winning form at Feyenoord. One will lose out.

Australian Associated Press