The injury concerns are mounting for Wales ahead of the Six Nations, with Dan Lydiate in danger of missing the entire campaign.
Flanker Lydiate sustained a bicep injury during the Ospreys' 22-9 victory over the Dragons on Sunday, ruling him out of their crunch European Champions Cup pool matches against Saracens and Clermont Auvergne this month.
Wales have already lost captain Sam Warburton and Taulupe Faletau to knee injuries, while Hallam Amos is a doubt for the start of the Six Nations.
Ospreys defence coach Brad Davis said the British and Irish Lion could be back within just six weeks, but he has known such injuries to rule players out for four months and require surgery.
Asked if there was a chance Lydiate could miss the Six Nations, Davis responded: "It's too early to tell, but there is a risk there, yes.
"I know players before who have had bicep tears and have had operations and been out for 12 to 16 weeks, possibly longer. It really depends on the extent of the injury.
"The best-case scenario is six to eight weeks. The worst case is they have to operate.
"We'll know a lot more about that once he has a scan and the medics can plan the way forward."
Wales get the Six Nations underway when they entertain Scotland in Cardiff on February 3.