Taulupe Faletau has been ruled out of Wales’ first three games of the Six Nations.
The 35-year-old suffered a calf injury while playing for Cardiff against Ospreys on 1 January.
The British and Irish Lions’ number eight had not long returned from a knee injury which sidelined him for Wales’ 2025 autumn internationals.
Cardiff coach Corniel van Zyl said: “It’s not clear on his return, but we’re definitely looking at the middle of the Six Nations, into our Leinster game [on 27 February].”
That would rule Faletau out of Wales’ opener against England on 7 February, along with the visits to Cardiff of France on 15 February and Scotland on 21 February.
“That is the target, we will see how it goes,” added van Zyl.
Wales head coach Steve Tandy will name his Six Nations squad on 20 January.
He is already without captain Jac Morgan and Gloucester centre Max Llewellyn for at least the first half of the tournament through injury.
Tandy’s number eight choices in the autumn included Aaron Wainwright, Olly Cracknell, Taine Plumtree and Morgan Morse, while Ross Moriarty could return to provide another option.
