Roberts will win his second cap in Bloemfontein

Winger Jamie Roberts says being picked to play full-back for Wales in South Africa will be a "big challenge".

The 21-year-old Cardiff Blues star won his first and only cap for Wales as a winger earlier this year in the 30-15 Six Nations win over Scotland.

He has also played most of his games for the Blues this season on the wing but sees his future as a full-back for both region and country.

"I think my game is more suited to full-back than wing," he said.

The 6ft 4ins back recently signed a three-year contract with the Blues and openly stated that he wanted to play more games at full-back for the region next year.

606: DEBATE Is Jamie Roberts experienced enough to perform at full-back against the Springboks?

Now he will get his chance to prove himself as the last line of defence on Saturday after Wales coach Warren Gatland chose him to replace knee-injury victim and first-choice full-back Lee Byrne.

Roberts, who combines playing rugby with his medical studies at the University of Wales in Cardiff, will not be completely out of practice after several outings in his favoured position this season.

"I've been fortunate to play three or four games at full-back for the Blues and though the skills do interchange it is a different position," he said.

"But playing the world champions in their back yard in a position I haven't played much is a big challenge for me."

Roberts is just one of a couple of shock inclusions by Gatland who will be playing out of his comfort zone in the first test in Bloemfontein.

The Kiwi coach has also recalled Llanelli Scarlets flanker Dafydd Jones to play open-side more than two years after his last appearance despite his normal position being at blind-side.