Cardiff Blues coach Dai Young is bracing himself for his side's biggest game of the season without his club captain.
Young watched on as skipper Paul Tito limped from the field in last weekend's 21-20 defeat to Magners League title holders Leinster.
Tito picked up a knee strain, and his inclusion in the squad that travel to Kingsholm for Sunday's crunch Heineken Cup clash is unlikely, according to Young who told the Western Mail: "Paul is very, very doubtful.
"It's very unlikely he will be fit for the Gloucester game, but he should be fit for the visit of Calvisano."
But Young has been told the injury will not keep Tito out of action for long. He explained: "It isn't a long-term problem, but he has strained his medial ligament in his knee."
The Blues still have work to do to qualify from Pool Six of the Heineken Cup and repeat last season's achievement of reaching the final eight.
Home advantage is crucial in European competition - as the Blues learnt when they were defeated by Toulouse last year. And the winners of the Kingsholm clash look likely to secure top spot and a home draw for the quarter-finals.
Cardiff have won all four of their matches to date, and have 18 points, meaning they sit top of the Pool - but have not yet confirmed their quarter-final qualification. They host Calvisano in the final match and would expect to take maxiumum points against a side who have failed to win a Heineken Cup match this season.
Gloucester's only defeat was at the hands of the Blues in Round 2, Cardiff "won ugly" on that day, according to Young. They would take another ugly result on Sunday.
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.