JAMES Thomas is the unlucky victim of Newport Gwent Dragons' back row selection headache for Sunday's Guinness Pro12 derby with the Ospreys.

The 24-year-old flanker has been in supreme form since getting his chance through others' injury misfortunes.

Thomas signed a professional contract after impressing with Bedwas in the Premiership last season and expected to be a fringe figure.

However, the Cardiff University student has been a roaring success, making 15 appearances and catching the eye with a pair of abrasive performances in the festive derbies against Cardiff Blues.

But, as Ospreys openside Justin Tipuric knows to his cost at Test level, four into three doesn't go.

Wales and Lions number eight Taulupe Faletau is the region's best player, scavenging seven Nic Cudd has been immense and Lewis Evans is a hugely influential figure in both attack and defence.

That means Thomas has to be content with a place on the bench for the trip to the Liberty Stadium and in the long run it will no doubt do him some good after a hectic schedule for a forward who was playing semi-professional rugby last year, especially with Six Nations duty looming for Faletau.

It will also give the Dragons some oomph off the bench and it was notable in the disappointing 11-9 home loss to Cardiff Blues last weekend that management team opted not to use forward replacements Andy Powell, Owen Evans and Hugh Gustafson.

Director of rugby Lyn Jones makes one other change to the XV that lost to the Blues with Jonathan Evans preferred to Richie Rees at scrum-half.

Hooker Rhys Buckley has made a faster recovery than expected from his October operation on a torn pectoral muscle and backs up Elliot Dee from the bench. Tighthead Lloyd Fairbrother and lock Matthew Screech get the nod ahead of Dan Way and Cory Hill to be among the replacements.

The Dragons will hope that they don't suffer from the law of the ex with former players Dan Lydiate, Dan Evans, Richard Fussell and Sam Parry all starting for the Ospreys. Rhys Webb and Dan Biggar are reunited at half-back after the former missed the derby defeat in Llanelli.

The Scarlets showed that the Pro12 pacesetters are a touch vulnerable at the set piece because of a lengthy injury list and the Dragons will hope to put their impressive driving lineout, which destroyed the Ospreys' second string an 53-35 LV= Cup win last autumn, to good use.

Steve Tandy has attempted to solidify the scrum by handing a start to former Wales loosehead Duncan Jones at the expense of Marc Thomas.

The Dragons have won just once on their travels to the Ospreys in the league when Faletau and scrum-half Wayne Evans scored tries in a 21-16 success in October, 2010.

The hosts include five players that featured in that game – Ashley Beck, Fussell, Webb, Duncan Jones and Tipuric – while Faletau, loosehead Phil Price, lock Andrew Coombs and fly-half Jason Tovey are looking for a repeat.

Ospreys: D Evans, R Fussell, A Beck, J Matavesi, E Walker, D Biggar, R Webb, D Jones, S Parry, D Arhip, J King, A W Jones (captain), D Lydiate, J Tipuric, T Ardron. Replacements: S Baldwin, G Thomas, A Jarvis, R Bernardo, S Lewis, M Roberts, S Davies, H Dirksen.

Dragons: T Prydie, M Pewtner, T Morgan, J Dixon, H Amos, J Tovey, J Evans, P Price, E Dee, B Harris, A Coombs, R Landman (captain), L Evans, N Cudd, T Faletau. Replacements: R Buckley, O Evans, L Fairbrother, M Screech, J Thomas, R Rees, D Jones, G R Jones.

Referee: Dudley Phillips (Ireland)