Wales flanker Dan Lydiate is likely to miss the November international programme, including a clash with the Wallabies, after suffering an ankle injury playing for Newport Gwent Dragons against Edinburgh in the Celtic League.
The 24-year-old, the player of the tournament when Wales won the Six Nations Grand Slam last season, went off just three minutes into Friday's match at Newport's Rodney Parade ground.
Lydiate, who has been regarded as a leading candidate for a place in next year's British and Irish Lions squad for the tour of Australia, was unable to put any weight on his left leg.
BBC Sport Wales have reported he is set to undergo surgery on Sunday amid indications Lydiate had suffered a fractured and dislocated ankle.
Wales play the first of four autumn Tests against Argentina in Cardiff on November 10 and if Lydiate's injury is as serious as first thought, there could be doubts over his availability for the Six Nations in February and March.