The 30-year-old sustained the injury in his regions 22-9 victory away against the Dragons on New Year’s Eve.
The 62 times capped Wales international will undergo surgery this week meaning he will miss the Six Nations.
“Dan is hugely frustrated but if there’s any light at the end of the tunnel it’s the fact he’s injured a different part of his body,” said Ospreys forwards coach Allen Clarke.
“It’s not a recurring injury at least it’s something that’s reparable and he can come back stronger. For us and for Dan it’s hugely frustrating but you have to have a positive mentality. You look at players these days and a lot of them are playing until they are 34/35.
“I suppose it’s about how many miles are on the clock. There may not be many miles on the clock in terms of playing time so hopefully he’ll get that at the back end of his career because he’s a fantastic individual and a pretty decent rugby player. We want him back fit and healthy as soon as possible.”
Since damaging his shoulder and hamstring captaining Wales in a pre-tour Test against England at Twickenham in 2016, the former Dragon has featured in just 12 games for his region and five for his country. Warren Gatland is already without back-row stars Sam Warburton and Taulupe Faletau for the Championship.
Lydiate captained Wales last Autumn against Georgia and was in contention to be selected in Wales’ Six Nations squad.
“I’m sure it’s worrying for Wales when you look at the number of injuries that Wales have in their back-row alone,” said Clarke.
