Welsh international flanker Robin Sowden-Taylor is unlikely to play again this season after suffering a serious injury during Cardiff Blues' Magners League defeat against the Ospreys.
The Blues forward was carried off just minutes from the end of last night's Liberty Stadium clash, which Cardiff lost 18-16.
The injury has been confirmed as a fracture and dislocation of his right ankle, meaning a prolonged absence from the game.
"It is a cruel blow for Robin," said Blues backs coach Rob Howley.
"He was only on for a matter of minutes, and one has to feel for him in that situation. Robin has been so patient over the last two years it makes it doubly frustrating for him."
Sowden-Taylor, 24, has won three caps and he would have been a contender for new Wales coach Gareth Jenkins' autumn Test squad ahead of games against Australia, Pacific Islands, Canada and New Zealand.
England's preparations for the Autumn International series were potentially dealt a further blow as Maro Itoje was forced to undergo an x-ray after Saracens' European victory over Scarlets on Saturday night.