Richie Rees and Lloyd Williams face a race against time to be fit for Cardiff Blues' Heineken Cup opener against Edinburgh.
Rees has currently missed almost a month of action with a calf injury, while Williams has been sidelined with a dead leg.
And although the scrum-half duo returned to training on Tuesday, they will have to prove their fitness to boss David Young.
However, with Wales international Gareth Cooper available, Young is pleased with the strength-in-depth of his squad.
Young told the Western Mail: "We have got good competition for places and everyone's performances have had to step up because of that, which is great from my point of view.
"We have got some stand-out players and it takes some real quality to get the jersey off them.
"But it doesn't give me a headache now if one of our more recognised players can't play because of injury. The next guy can step up, whereas in the past it's been fingers crossed that nobody gets injured."