So much for using the United Eagles match as the final Wallabies' best XV run-through before the Rugby World Cup. Instead, the team that jogs onto Soldier Field in Chicago on Saturday will bear only scanty resemblance to the line-ups Australia will use in their opening World Cup matches against Fiji and Uruguay.

The Chicago venture is being used as a moment to reward the dedicated, keep the fringe candidates interested, and see whether certain combinations may be worth trying during the tournament.

The reward goes to James Slipper, who becomes the 83rd player to skipper his country.

The fringe candidates like Toby Smith will remain focused by being placed on the bench. Sam Carter, James Hanson and Taqele Naiyaravoro, who all failed to make the World Cup squad, meanwhile discover that their venture to the United States is not just to take some happy snaps but also to get a bit of a runaround in the second half of the Chicago Test.

James Slipper © Australian Rugby Union

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And the combination experiment revolves around the second-row; if Kane Douglas and Rob Simmons combine well against the Eagles, they could easily be kept there for the bulk of the World Cup. This is their big chance.

You also must remember that Wallabies coach Michael Cheika will do all he can to ensure that Douglas is used extensively during the tournament, especially after it cost Australian Rugby around $Aus300,000 in transfer fees to ensure he was able to return from Ireland. The Australian team management is not going to waste that investment.

This is also a chance to see whether the Waratahs halves combination of Nick Phipps and Bernard Foley can get their bearings back after they lost their way in the Bledisloe Cup Test in Sydney. This game, which should result in a comfortable Wallabies win, is the ideal time for both of them to regain confidence.

What can be assured is that the team that confronts Fiji in Cardiff on September 23 in Australia's opening World Cup match will be drastically different to what appears against the Eagles.