Ashley Beck has been ruled out for six to eight weeks.
Wales and the Ospreys have been dealt a blow after Ashley Beck was ruled out for up to two months.
The centre suffered an ankle injury during his try-scoring cameo against Newport Gwent Dragons on New Year's Eve.
And following further investigation it has been discovered that the 22-year-old has suffered significant ligament damage.
He will subsequently miss the Ospreys crucial Heineken Cup matches with Leicester Tigers and Benetton Treviso and at least the first three fixtures of the RBS 6 Nations, against Ireland, France and Italy.
"Ashley suffered a significant ligament injury to his ankle during the New Year's Eve fixture at Rodney Parade," said Ospreys head of physio.
"We've conducted investigations over the course of the last week to determine the full extent of the ligament damage and plan his rehabilitation effectively.
"Based on the advice received, we are currently treating this as a 6-8 week injury so would expect to see him back in action by the end of February."
Jamie Roberts and Jon Davies remain the tried and tested combination in the Welsh midfield, while the likes of Scott Williams and James Hook offer further options.
As the countdown continues for RWC2015, Tournament Chief Executive Debbie Jevans visited the Millennium Stadium to discuss preparations for the eight matches and reveal the positive news that 100,000 tickets for games at the home of Welsh rugby have sold in the last seven days.
Jason Harries is targeting a first win on the World Series circuit this season with Wales. The series returns to action this weekend in Dubai where Harries is part of a team hoping to build from its efforts in round one in October.
Wales skipper Jevon Groves says his side have addressed a few points from Gold Coast and aim to 'hit the ground running' in the next two rounds of the World Series, kicking off with this weekend in Dubai before heading off to South Africa next week.
Wales Sevens manager Steff Thomas is hopeful his side can build from a quarter-final spot in the opening round of the World Series in Australia when his side take part in the forthcoming double header in Dubai and South Africa.