England winger Anthony Watson is likely to miss the autumn Tests after breaking his jaw.
The Bath player, 22, was injured earlier this week during regular practice at England's training camp.
Flanker Sam Jones is also set to miss the matches against South Africa, Fiji, Argentina and Australia after breaking a leg in a judo session in training.
The Wasps man, 24, fractured a fibula while grappling with lock Maro Itoje at the training camp in Brighton.
It was England's final session before head coach Eddie Jones names his squad for the four Test matches.
Watson, who has scored 12 tries in 24 Tests, has been a regular starter for Jones' side, playing every game of their successful Six Nations campaign and the 3-0 whitewash in Australia.
"It's too early for a full medical prognosis on how long he'll be out for, but it's likely he'll miss the autumn internationals," said Bath director of rugby Todd Blackadder.
"He's in great hands with our medical team and we look forward to seeing him back on the pitch when he's ready."
|England's autumn Tests|
|Saturday, 12 November||South Africa|
|Saturday, 19 November||Fiji|
|Saturday, 26 November||Argentina|
|Saturday, 3 December||Australia|
|*All matches at Twickenham|
Flanker James Haskell, back rower Jack Clifford and centre Manu Tuilagi will also miss all of England's autumn Tests through injury.
Fly-half Owen Farrell and captain Dylan Hartley have both yet to play this season because of back problems.