Flanker Sam Jones is set to miss England's autumn Tests after breaking his leg in a judo session in training.
The Wasps man, 24, suffered a fractured fibula while grappling with lock Maro Itoje at the training camp in Brighton.
It was England's final training session before head coach Eddie Jones names his squad to face South Africa, Fiji, Argentina and Australia.
The uncapped Jones had hoped to replace the injured James Haskell at seven for the Tests in November and December.
Coach Eddie Jones has introduced judo sessions to help players develop skills that will be useful in the tackle area, with double Olympic medallist Kate Howey and GB coach JP Bell putting the England squad through their paces on Monday.
Dai Young, director of rugby at Sam Jones' club Wasps, said: "I really feel for Sam - he has worked his socks off for Wasps and deservedly got his call-up to England."
An X-ray confirmed a fracture of the right leg and the club is awaiting results of MRI scans to determine the full extent of the damage.
"Our medics and physios will look after him and we look forward to having him back when he is ready," Young added.