MARTIN Roberts will make his Wales debut this week in a dress rehearsal for the full-scale Millennium Stadium production that awaits him later this month.

Wales boss Warren Gatland looks certain to be without both premier scrum-halves - Lions Gareth Cooper and Dwayne Peel - for the November 29 clash against Australia.

Because the Wallabies encounter - Wales' fourth November Test - falls outside the International Rugby Board's autumn window, their respective Guinness Premiership clubs Sale Sharks and Gloucester have first call that weekend.

Sale host Leicester and Gloucester Northampton, although Wales were prepared to make a deal by releasing Peel for a Premiership appointment with Worcester in four days' time, rather than him being involved against Canada.

Scarlets scrum-half Roberts, though, will start the Canada game on Friday night - and he is set to reclaim the jersey when Australia arrive in Cardiff a fortnight later.

Peel, meanwhile, is among the replacements for Canada's visit - with Cooper not involved.

Gatland said: "We've got to plan for the two scrum-halves not being there (against Australia).

"At the moment, with it being unlikely Dwayne Peel and Gareth Cooper will be available for the Australia game, I thought it would be pretty unfair to throw the young kid (Roberts) in against Australia without him having a run.’’ Roberts, 22, knows rugby union's contentious player-release issue is set to work in his favour - but he added: "I think it is something that needs to be sorted out.

"At the end of the day, it is the players who are getting affected by it.’’ Roberts is among 12 changes made by Gatland following the 20-15 defeat against world champions South Africa two days ago.

Only captain Ryan Jones, wing Leigh Halfpenny and centre Tom Shanklin remain - while two players, Sale prop Eifion Roberts and Ospreys fly-half Dan Biggar, could be handed their first caps off the bench.

There is a surprise call-up from outside Gatland's initial 32-man autumn Test squad for Cardiff Blues prop John Yapp.

He packs down in the front row, after Ospreys loosehead Duncan Jones was ruled out by a foot injury.

Yapp's Blues colleague, wing Tom James, could also be summoned by Gatland if full-back Morgan Stoddart fails a fitness test.

Stoddart faces checks on an ankle injury tomorrow - and if he is ruled unfit then Halfpenny will replace him at full-back, with James starting on the wing.

Both Yapp and James are now officially part of the Wales squad.

For Roberts, Wales recognition comes at the end of a year that started with him struggling to make an impact in a star-studded Ospreys squad.

"It has come very quickly,’’ he admitted.

"If I look back five months ago, I was getting an odd game now and again with the Ospreys - and things weren't looking promising.

"The move to the Scarlets has helped, and I must have played well enough for them to be recognised.

"It is just about getting the opportunity to play regular rugby.

"When you play once every couple of games you feel as if you have to go out and impress all the time.

"But when you know you are going to get a regular run of matches, you can play your own game. You don't feel pressured into trying to impress the coach.’’ Captain Jones moves from blindside flanker to his more familiar number eight role instead of Andy Powell - who was man-of-the-match against South Africa, with flanker positions taken by Dafydd Jones and Robin Sowden-Taylor.

It is all change in the front five - where there is a rare start for 6ft 9in Newport Gwent Dragons lock Luke Charteris, while Scarlets wing Mark Jones returns following a knee injury.

Gatland added: "I was really pleased with Andy's performance on Saturday. We are saving him for the All Blacks.

"Ryan's performance at six, in terms of his effort and work-rate, was outstanding - so we wanted him to go back into a familiar position and again lead the team from the front.

"We have a short turnaround before we face Canada, and this was always going to be a game in which we tried to utilise our squad.

"We have a chance to put defeat against South Africa behind us and really try to build some momentum before New Zealand and Australia come to town, so we know what we need to achieve against Canada.

"There are lots of changes from the weekend. But we have maintained consistency by keeping Ryan in there as captain and we have some experience and impact players, too, on the bench.’’