Uncapped Wasps flanker Jack Willis will miss England's South Africa tour after suffering a serious knee injury that could sideline him for up to a year.
Wasps say that Willis sustained "a significant multi-ligament injury" during last Saturday's 57-33 Aviva Premiership play-off defeat at Saracens and is expected to be out for nine to 12 months.
Such a lengthy absence would also end his hopes of challenging for England recognition during the autumn Tests next season, and potentially the 2019 Six Nations Championship.
Willis had to be helped from the pitch following a first-half tackle by Saracens fly-half Owen Farrell at Allianz Park.
In a statement, Wasps said: "Following consultation with a specialist, it has been determined that Jack Willis sustained a significant multi-ligament injury to his right knee during last Saturday's Aviva Premiership semi-final.
"This includes a rupture of his anterior cruciate ligament (ACL).
"The injury is expected to keep him out of action for a period of between nine and 12 months."
Willis, 21, was among 12 back-five forwards named in a 34-man summer tour squad by England head coach Eddie Jones.
His absence from next month's three-Test trip could now see a call-up for his Wasps colleague Nathan Hughes, who returned from injury in the Saracens game.
In-form Exeter flanker Don Armand, who is currently preparing for Saturday's Premiership final against Saracens at Twickenham, would be another potential option.
England face the Springboks in Johannesburg, Bloemfontein and Cape Town from June 9-23.
England Under-20 international Willis was promoted to Wasps' senior squad last summer, and he has impressed on a consistent basis in club colours.