Last updated on .From the section Welsh Rugby

Ollie Griffiths won his only Wales cap on their 2017 summer tour when they beat Tonga in Auckland.

Guinness Pro14: Cardiff Blues v Dragons Venue: Cardiff Arms Park Date: Friday, 21 Dec Kick-off: 19:35 GMT Coverage: Live commentary on BBC Radio Wales, Radio Cymru the BBC Sport website and app

Dragons will be without influential back-rower Ollie Griffiths for their Pro14 derbies against Cardiff Blues, Ospreys and Scarlets.

The once-capped Wales international, 23, suffered a knee injury in the European Challenge Cup defeat at Northampton on 8 December.

Wales centre Tyler Morgan is concussed and will also miss Dragons' trip to Cardiff Blues on Friday, 21 December.

However, veteran Wales hooker Richard Hibbard is expected back for that game.

Hibbard could be joined by fit-again wing Jared Rosser and back-rower Harrison Keddie for the first Welsh derby of the festive period.

But a hamstring tear that needs surgery has ruled out fly-half Arwel Robson, who is not expected to return until the latter stages of 2018-19 at the earliest.

Griffiths, who can play across the back-row, missed last weekend's losing rematch against Saints and is out for up to six weeks.

After facing Cardiff Blues, Dragons host Ospreys on Sunday, 30 December and are at Scarlets on Saturday, 5 January.