Joel Tomkins set for England debut but Geoff Parling out
Rugby league convert Joel Tomkins is set for an England debut against Australia at Twickenham on Saturday - but head coach Stuart Lancaster will be without lock Geoff Parling.
Uncapped Saracens centre Tomkins, who switched codes in 2011, has been retained in Lancaster's 23-man squad.
But Lions second-row Parling suffered mild concussion during training on Tuesday and has been ruled out.
Parling's absence means Courtney Lawes and Joe Launchbury are likely to start.
Bath's Dave Attwood, who only returned from a rib injury last week, will supply second-row cover from the bench for the opening autumn Test against the Wallabies.
Leicester Tigers' Parling will stay with the squad, however, and is expected to return to training ahead of next week's Test against Argentina at Twickenham.
Parling joins prop Alex Corbisiero on the injured list after the the Northampton man sustained a knee injury a fortnight ago.
Lancaster allowed 11 players to return to Premiership duty with their clubs, including uncapped Gloucester centre Henry Trinder and fellow backs Luther Burrell (Northampton Saints), Kyle Eastmond (Bath Rugby), Christian Wade (London Wasps) and Freddie Burns (Gloucester).
They were joined by forwards Matt Kvesic (Gloucester Rugby) and Tom Johnson (Exeter Chiefs).
Lancaster will have to choose between Ben Youngs and Lee Dickson at scrum-half after Danny Care was released, while Ben Foden was retained in the squad following his impressive two-try display for Saints against Saracens.
"It's never easy deciding who to select and that's what you want, players pushing hard for places across the board," said Lancaster.
"We have had two good days of training here at Pennyhill Park and, added to last week in Leeds, we are in good form and looking forward to the game."
England 23-man squad:
Backs: Chris Ashton (Saracens), Mike Brown (Harlequins), Ben Foden (Northampton Saints), Marland Yarde (London Irish); Joel Tomkins (Saracens), Billy Twelvetrees (Gloucester Rugby); Owen Farrell (Saracens), Toby Flood (Leicester Tigers); Lee Dickson (Northampton Saints), Ben Youngs (Leicester Tigers).
Forwards: Dylan Hartley (Northampton Saints), Tom Youngs (Leicester Tigers); Dan Cole (Leicester Tigers), Joe Marler (Harlequins), Mako Vunipola (Saracens), David Wilson (Bath Rugby); Dave Attwood (Bath Rugby), Joe Launchbury (London Wasps), Courtney Lawes (Northampton Saints); Ben Morgan (Gloucester Rugby), Chris Robshaw (Harlequins), Billy Vunipola (Saracens), Tom Wood (Northampton Saints).
Players released: F Burns (Gloucester), L Burrell (Northampton), D Care (Harlequins), K Eastmond (Rugby), A Goode (Saracens), T Johnson (Exeter), M Kvesic (Gloucester), H Thomas (Sale), H Trinder (Gloucester), R Webber (Bath), C Wade (Wasps).