Ashton was suspended for England's 54-12 victory over Fiji last weekend but he has been recalled to face the Wallabies, against whom he has scored three tries in three Tests.
The inclusion of Ashton is the only change to the match-day squad made by head coach Stuart Lancaster, who has decided not to rush Jonathan Joseph or Alex Corbisiero back into the squad.
Corbisiero played his first game in five months for the London Irish last weekend after recovering from a knee injury and Lancaster wants him to get another club game under his belt.
Joseph is fit again after shaking an ankle injury but he will join Corbisiero in being available for London Irish in their LV= Cup game against Leicester.
Lancaster will finalise his starting XV on Thursday morning but Ashton and Charlie Sharples are the likely wing selections, with Monye released to play for Harlequins.
Wasps lock Joe Launchbury is pushing hard for a first Test start while Thomas Waldrom appears to have retained the number eight shirt after Ben Morgan was among 13 players released.
Manu Tuilagi has not trained this week and he spent all day today undergoing rehabilitation on a sprained foot but England are confident he will be fit to play on Saturday.