Ben Blair will play no part in the remaining Heineken Cup Pool matches after he suffered a broken hand in a Magners League defeat to the Ospreys on New Years Day.
Cardiff Blues have confirmed Blair has a very small fracture in a bone in his right hand, which has been put in a cast to protect it.
Blair will see a hand specialist on Monday and it is thought that the injury could keep him out of action for up to four weeks.
The New Zealand international fractured the 4th metacarpal bone in the match against the Ospreys on New Year's Eve and his hand is now healing in a splint.
This means the the goal kicking Kiwi will miss the crucial match with Gloucester at the end of the month.
The Blues may have a 100 per cent record in Pool 6, but with Gloucester also performing well, the Kingsholm tussle is likely to be a Pool decider, and the Blues know only too well the cost of coming second in the group stage.
Failure to progress in first place last season meant a trip to Toulouse in the quarter-finals of Europe toughest club competition. The result went the way of the three-times champions and now, Blues boss Dai Young must wait on medical results to see if his goal-kicking full back can help his side into the final eight.
Blair walked off midway through the first half with an ice bag on his hand during his side's 16-12 defeat to their regional neighbours.
Meanwhile, Martyn Williams, the Wales and Lions flanker, was another to leave the field clutching his shoulder, but he is expected to be fit.
"Martyn has struggled throughout the Autumn Test series with a shoulder injury," said Young.
"We rested him for two weeks and he just took another bang on it. There is nothing which needs an operation and nothing to be worried about there."
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.