England have added Harlequins back-row Jack Clifford to their squad ahead of Saturday's Test against Australia.
Clifford comes in as Billy Vunipola was ruled out for 12 weeks after undergoing knee surgery on Sunday. But there are no guarantees Clifford will be fit for the weekend's match as he will be assessed by England's medics this week after requiring a Head Injury Assessment in Harlequins' win over Bath on Sunday.
Sunday's match -- one where Clifford was named Man of the Match -- was his first since suffering an ankle injury in September.
With Vunipola absent, England will also be monitoring Nathan Hughes' fitness with the Wasps No.8 nursing a foot injury while Josh Beaumont and Teimana Harrison will also be in contention to start in the back-row.
Elliot Daly is omitted from the squad as he faces a disciplinary panel on Monday following his red card against Argentina. Both Semesa Rokoduguni and Marland Yarde do make the cut in the 33-man squad and will be in the frame to start against the Wallabies if Daly is handed a suspension.
England squad for Australia:
Forwards (19): Dave Attwood (Bath Rugby), Josh Beaumont (Sale Sharks), Dan Cole (Leicester Tigers), Jack Clifford (Harlequins), Charlie Ewels (Bath Rugby), Ellis Genge (Leicester Tigers), Jamie George (Saracens), Teimana Harrison (Northampton Saints), Dylan Hartley (Northampton Saints), Nathan Hughes (Wasps), George Kruis (Saracens), Joe Launchbury (Wasps), Courtney Lawes (Northampton Saints), Joe Marler (Harlequins), Chris Robshaw (Harlequins), Kyle Sinckler (Harlequins), Tommy Taylor (Wasps), Mako Vunipola (Saracens), Tom Wood (Northampton Saints).
Backs (14): Mike Brown (Harlequins), Danny Care (Harlequins), Owen Farrell (Saracens), George Ford (Bath Rugby), Alex Goode (Saracens), Mike Haley (Sale Sharks), Jonathan Joseph (Bath Rugby), Alex Lozowski (Saracens), Jonny May (Gloucester Rugby), Semesa Rokoduguni (Bath Rugby), Henry Slade (Exeter Chiefs), Ben Te'o (Worcester Warriors), Marland Yarde (Harlequins), Ben Youngs (Leicester Tigers)