Under previous boss Ange Postecoglou, it is unlikely there would have been any doubt about Milligan's selection. The ex-Socceroos boss coached him at Melbourne Victory and made him a crucial part of the national set-up, so it is unthinkable that he might miss out.

New Socceroos boss Bert van Marwijk will look at everything through fresh eyes, but it is unlikely - given his status within the squad, his experience and his track record - Milligan will miss out. That said, new coaches do not always make choices that are expected.

Milligan has been to three world cups, but only played briefly in one, in Brazil in 2014.

The first time he was selected was as an A-League player in 2006, when he was taken as a 20-year-old for the experience. In 2010 he was a squad player too, playing in China and Japan in the lead-up.

In 2014, Milligan was one of a handful of A-League players to get a call-up for Brazil. By then he was an established player, although his contribution in Brazil was limited by injury.

The strength of the Saudi Arabian Pro-League, home of Milligan's new employers, Al Ahli, is hard to judge, although few coaches will have a better understanding of it than van Marwijk, who watched plenty of it when he was coaching the Saudi national team.

Al Ahli is one of the biggest clubs in the country, and finished runners-up in the league in the 2016-17 season, when they were also runners-up in the Kings Cup. After 17 games this season the club is second on the ladder, with 34 points from 17 games, two behind leaders Al Hilal.

Milligan and his advisers will have come to the conclusion that whatever happens, his move back to the Middle East was in his best interests.

Whether it was in Victory's remains to be seen.

It provides Victory with a major headache with just a couple of days remaining in the transfer window but it is unclear whether they will try and move quickly to plug the gap or try to make do with what they have got.

The club is understood to have received $US600,000 for a player who would have been able to leave for nothing in a couple of months, so from a financial point of view Milligan's departure is good business.

But it does leave Victory short in midfield. The signing of Terry Antonis earlier in the transfer window now looks like a shrewd move, as he can slot into the central midfield role that Milligan held, with Argentinian Matias Sanchez available as a reserve. Leigh Broxham, if not required as a full-back, is also an option in the middle.

At 32, Milligan's best days are behind him, and he had not been asserting himself in A-League games as much this season. But Victory coach Kevin Muscat will undoubtedly find it difficult to replace him.