England scrum-half Alex Mitchell will miss Saturday's Six Nations match against Scotland due to a knee injury.
The 26-year-old is likely to be replaced by either Danny Care or Ben Spencer in the Calcutta Cup clash at Murrayfield.
Bristol scrum-half Harry Randall has been called up as cover in Steve Borthwick's 36-man training squad.
An England spokesperson said Mitchell's injury required “further investigation” to determine the severity.
Mitchell has started in both of England's Six Nations wins against Italy and Wales.
The Northampton Saints scrum-half has established himself as England's first choice since joining the team ahead of last autumn's World Cup.
England are second in the Six Nations standings behind defending champions Ireland with eight points.
There will be full commentary on Scotland vs England next Saturday, kicking off at 4.45pm on BBC 5 Live, and all the latest news will be available on your TV. rugby union daily podcast With BBC Sound.
England national team plays against Scotland
forward: Ollie Chetham (Leicester Tigers), Dan Cole (Leicester Tigers), Alex Coles (Northampton Saints), Luke Cowan-Dickie (Sale Sharks), Chandler Cunningham-South (Harlequins), Ben Currie (Sale Sharks), Theo Dunne (Saracens), Alex Dombrandt (Harlequins), Ben Earl (Saracens), Charlie Ewells (Bath Rugby), Ellis Genge (Bristol Bears), Jamie George (Saracens), Joe Hayes (Leicester Tigers), Maro Itoje (Saracens), Joe Marler (Harlequins), George Martin (Leicester Tigers), Beno Obano (Bath Rugby) ), Ethan Roots (Exeter Chiefs), Will Stewart (Bath Rugby), Sam Underhill (Bath Rugby)
Bucks: Danny Care (Harlequins), Elliot Daly (Saracens), Fraser Dingwall (Northampton Saints), Immanuel Fay-Waboso (Exeter Chiefs), George Ford (Sale Sharks), Tommy Freeman (Northampton) Saints), George Firbank (Northampton Saints), Olly Lawrence (Bath Rugby), Max Ojomoh (Bath Rugby), Harry Randall (Bristol Bears), Tom Roebuck (Sale Sharks), Henry Slade (Exeter Chiefs), Finn Smith (Northampton Saints), Ben Spencer (Bath Rugby), Freddie Steward (Leicester Tigers), Manu Tuilagi (Sale Sharks)
