Ospreys will be without veteran Wales captain Alun Wyn Jones when they host Castres in their 2020-21 European Challenge Cup opener on Saturday.

Ospreys boss Toby Booth and Jones are awaiting a medical report on the medial ligament injury.

"It's going to be weeks not days," said Booth.

That leaves Ospreys not knowing how many games the lock will miss after he came off in the second half of Wales' 38-18 win against the Azzurri that earned them fifth place in the tournament's final rankings.

Booth added: "I can't tell you that [how many games Jones will miss]. I don't know.

"Until we get the full picture on the scan, until we get recommendations from the consultants... I know Wales will be involved because he was in their charge, if you like, at the time.

"So there's a few people who'll need to compare notes.

"But I can't answer the question, not because I don't want to but because I don't know.

"It's disappointing because you want your best players," said Booth.

"But having a percentage of injured people is in the nature of what we do. We play an attritional sport.

"We need to make sure we cope as best we can.

"It's no different from an international window. For us, not a lot has changed in relation to who we have available in that position.

"But, yes, the leadership and the stuff around his position, his effectiveness in that position, is something that's hard to compensate for.

"But it also provides an opportunity for other people to put up their hands and grow a little into that role."