Following an X-ray, Wasps have confirmed that flanker Sam Jones has suffered a fracture of his right leg (fibula) during England training.
The club is awaiting the results of subsequent MRI scans and Jones will see a specialist on Friday to determine the extent of the injury.
Wasps' director of rugby Dai Young said: "It's a big blow and I really feel for Sam, because he has worked his socks off for Wasps and deservedly got his call-up to England. Sam has been one of the first names on my team sheet this season and he will be a big loss for us, but we are lucky to have a lot of talented back rowers at the club who have already stepped up this season.
"My biggest disappointment is for Sam as he's been playing so well and I'm sure would have made a good impression in the England camp. These things happen, but you can't help but feel sorry for him. It's too soon to know how long he will be out, but our medics and physios will look after him and we look forward to having him back when he is ready."