The Ospreys are sweating on the fitness of star duo Ashley Beck and Justin Tipuric ahead of the crunch Heineken Cup clash with Leicester Tigers.
The Swansea-based region must maul the Tigers to keep their European hopes alive but could be without the international pair.
Beck is unlikely to recover from an ankle injury in time and Tipuric's chances are rated at 50/50.
"Tips is doing some rehab and is 50-50, but we are waiting on some extra information on Ashley Beck, who is a real doubt," said Ospreys head coach Steve Tandy.
"Tips has been huge for us, Becky, too. It something we've had to get used to this season, with senior players missing, people like Ian Evans, Alun Wyn Jones, Aaron Jarvis and Hanno Dirksen.
"If we lose Beck and Tips it will be a huge task for us, especially given the limited squad we have. But it's something we have to prepare for and we are going to give it a right old go."
Tandy was more hopeful of having Tipuric available for selection but he insists he will take no risks despite the magnitude of the game.
"There's always that temptation but we won't put the group before the player," said Tandy.
"If he's not right, he's not right. There are educated risks in what we are doing, but I need to sit down with the physio and see where they are come Friday.
Tom Issacs is set to fill the void left by Beck and Sam Lewis is a front-runner to start if Tipuric fails to recover.
And Tandy insists the Ospreys are confident of the duo coming in and producing the goods.
"We have no issues with TI (Isaacs) starting at 13 this weekend. He did really well for us there against the Scarlets earlier in the season.
"We'll weigh things up in the back-row, but we have a boy in Sam who's outstanding every time he wears the shirt.
"He was out on his feet at the end of the Zebre game, especially after his performance against the Dragons. He is developing all the time.
"You find out more about people on these big occasions and we are keen to develop from within. I know if Sam has to step into the role he won't let us down."
It was a double celebration for Wales and Ospreys scrum-half Rhys Webb when he called at the home of Welsh rugby to help commemorate the first anniversary of Principality Stadium and his return to fitness this weekend ahead of the RBS 6 Nations.
Prior to their departure to Wellington for the next leg of the World Series, Wales trained with England and Ireland. WRU TV caught up with Owen Jenkins who revealed the 'buzzword' which is driving the Wales squad on.
Wales head coach Rob Howley explains his decision to change the captaincy of the national side with Ospreys second row Alun Wyn Jones taking over from Sam Warburton for the forthcoming RBS 6 Nations. Howley is hoping his decision will allow Warburton to rediscover his 'mojo'.
How do you follow a dancing hippopotamus - the Ospreys wheelchair rugby team has just the 'oneness' to do it say the BBC! For a decade the sight of a herd of hippos synchronised swimming around their own private blue lagoon, has lit up our television screens at regular intervals between favourite BBC One shows. But now the nation's most watched channel has relinquished its famous amphibious mammals in favour of a new show-reel which includes the Ospreys wheelchair rugby team.
Head coach Rowland Phillips and key front rower Carys Phillips look ahead to games against Spain and Ireland as Wales Women ramp up their preparations for the forthcoming Six Nations. The two warm-up games are a 'massive opportunity to refine the squad' according to the Welsh camp.
Martyn Phillips has discussed details of the newly published 'Strategy for Welsh Rugby' which puts in black and white terms the plans and direction of the governing body of the national sport in Wales for the next decade.
WRU chief executive Martyn Phillips has urged Welsh rugby fans to follow in the footsteps of their soccer counterparts at last summer's Euro Championship by backing their team to the hilt in the upcoming RBS 6 Nations campaign.
Chief executive Martyn Phillips has highlighted the plans for Wales to become a breeding ground for national and elite club rugby coaches, which are contained in the WRU's 10-year 'Strategy for Welsh Rugby'.
Andrew Coombs is enjoying his new role as Nelson forwards coach. The former Dragons and Wales lock has big ambitions to become a professional coach but feels it's important to learn the ropes in grassroots rugby and where better than his home club Nelson, with friends and family close to hand.
Students at Brynllywarch Hall School, near Newtown, have transformed their own lives, and are now having a positive impact on others through rugby. The sport has had a life-changing effect on the well-being of the students who are now delivering rugby sessions to local primary schools and playing for a new mixed ability side
Wales reached their first semi-final since 2013 in the opening round of this season's HSBC World Rugby Sevens Series in Dubai. WRU TV's Graeme Gillespie recaps on what proved to be an eventful tournament
Wales and Ospreys back row James King, who came through the North Wales age grade system, nominated North Wales Regional Community Rugby Manager Marc Roberts, in the WRU's 'Diolch' initiative where squad players thanked those who played a part in their rise to the top.
Beating Merthyr has boosted Carmarthen Quins hopes of reaching a top eight spot in the Principality Premiership. Quins captain Haydn Pugh is delighted with his team's progress and is determined that everyone from the Under 6s through to the senior team, enjoys the ride.
When the Wales squad were asked to nominate individuals who played a big part in their early playing days, Wales and Dragons full back and wing Hallam Amos thought of his former Monmouth School rugby coach John Bevan.