Ospreys forward Sam Lewis will sit out the opening weeks of the new campaign after suffering a ligament injury against Saracens.
Although he doesn't need surgery, Lewis has been ruled out of action by Chris Towers, Medical Performance Manager at the region.
"Sam damaged his medial collateral ligament against Saracens. He has had the required tests and scans, confirming the extent of the problem, and it's good news in that no surgery is needed," said Towers.
"He will have to take time to recover and rehab fully, and at this stage we are looking at an eight week recovery period."
There was also an update on the fitness of Ryan Bevington, who hasn't played since injuring his groin on international duty with Wales during the Six Nations campaign earlier this year.
"Ryan has suffered a setback in his recovery and at the moment it's not possible to put an accurate timescale on his return to play," added Towers.
"We have sought a second opinion, and will continue with an intensive treatment and rehab programme with a viewing to getting him back on the field at the earliest opportunity."