England flanker Tom Croft could be out for six months, putting his World Cup hopes at risk, according to Leicester director of rugby Richard Cockerill.
The 29-year-old dislocated his shoulder during the Tigers' win over Newcastle earlier this month and faces a race to be fit for the World Cup, which begins on 18 September when England host Fiji.
Cockerill told BBC Radio Leicester: "He has had a bit of nerve damage as well.
"We hope it is as quick as possible but it's likely to be six months or so."
Croft has had surgery and faces another lengthy spell on the sidelines after an injury-plagued couple of seasons.
Having suffered a broken neck in 2012, Croft missed most of last season with a knee injury.
He has been capped 41 times by England since making his debut against France in 2008.
Cockerill added: "We just have to support the player and get him back on the field. It has been hugely disappointing for him and the club."