Paul Sackey has been ruled out of England's RBS 6 Nations clash against France at Twickenham on Sunday.
The Wasps wing was today released back to his club, having been unable to train with England at their Surrey base.
Sackey is struggling with a lower calf muscle injury that forced him off during England's 14-13 defeat against Ireland at Croke Park 10 days ago.
He is likely to be replaced in the starting line-up against France by Harlequins' Ugo Monye or Sale Sharks back Mathew Tait.
Harlequins scrum-half Danny Care, meanwhile, will be involved against France despite receiving widespread criticism following the yellow card he collected for a reckless push on Ireland prop Marcus Horan in Dublin.
The players who go back to their clubs ahead of this weekend's Guinness Premiership action are Sackey, Danny Cipriani, Steffon Armitage, George Chuter, Louis Deacon, Ben Foden, Luke Narraway, Jamie Noon, Olly Morgan, Tim Payne and Olly Barkley, plus two who were called up to the squad as injury cover earlier this week - Harlequins wing David Strettle and Newcastle prop David Wilson.
Barkley was summoned as a replacement for Shane Geraghty, who has been ruled out of the rest of the tournament.
London Irish back Geraghty broke a bone in his hand playing for Irish against Wasps two days ago.
Gloucester back-row forward Narraway will lose his place on the bench from Dublin, with Wasps' Simon Shaw set to be involved when England manager Martin Johnson announces his team and replacements to face France today.
England Under-18 head coach John Fletcher insists his young side will be better for the experience after beating Italy in the bronze final to round out their 2015 Rugby Europe U18 Championship campaign in style.