Wales captain Sam Warburton facing at least a month on the sidelines

Wales captain Sam Warburton will be out for at least four weeks with an ankle injury.

Warburton saw a specialist on Tuesday after suffering the injury in the Cardiff Blues' 13-6 Guinness PRO12 derby defeat at the Ospreys on Saturday.

"Sam has suffered a grade two strain to his right ankle and has now seen the specialist to start his recovery process," Blues head of medical services John Miles told the official club website.

"He will return to the specialist in a week's time for further assessment and currently we are working at a minimum lay-off of four weeks for a return to play."

Warburton suffered the injury in a tackle by Justin Tipuric, his rival for the openside flanker's position with Wales, and will miss the Blues' two European Challenge Cup matches against Montpellier in December.

The 27-year-old will also be absent for PRO12 Welsh derbies against the Newport Gwent Dragons and the Scarlets over Christmas.

Blues head coach Danny Wilson said: "We are hoping it is a four-week lay-off and Sam is a great professional who will work hard to get himself back as quick as possible."

Warburton will want to prove his fitness in January before Wales open their Six Nations campaign against Ireland in Dublin on February 7.