Wales have called up Toby Faletau to their squad for the Test against Australia on Saturday while Jonathan Davies has been ruled out of the clash.
Faletau, a 19-year-old Dragons flanker, will replace injured back-rower Rob McCusker, who withdrew from the squad last week to have a hernia operation.
Faletau, who is the son of former Tonga lock Kuli Faletau, graduates to the senior squad after representing the Under-20s in the Six Nations earlier this year.
Meanwhile, Davies has withdrawn from the squad after failing to recover from an ankle injury in time for the Wallabies' visit to the Millennium Stadium.
The Scarlets centre suffered ankle ligament damage in training last week.
Centres Dafydd Hewitt and Scott Williams and No. 8 Andy Powell are also training with the squad but have not received full call-ups, although the latter is unavailable for the match against Australia.
Besides Davies, Wales will also be without Lee Byrne (hand), Leigh Halfpenny (ankle) and Ryan Jones (calf) at the Millennium Stadium.
However, defence coach Shaun Edwards has vowed that Wales will "have a crack" at Australia, who have arrived in Cardiff having beaten New Zealand 26-24 at the weekend.
They return to the capital 12 months after beating Wales 33-12 in a triumph even more one-sided than the scoreline suggests.
It remains head coach Warren Gatland's heaviest home defeat but Edwards is determined to see Wales at least match Australia's threat this time.
"Obviously, they are a very formidable outfit at the moment," he said.
"The last two Test matches we've had against them, we've won one and they were very dominant in the last one, which still hurts.
"It is something that (Wales captain) Matthew Rees spoke about this week. We are still hurting from that defeat, and we hope to give a lot better account of ourselves.
"I thought in the Tri Nations this year, they (Australia) were the team playing the most rugby.
"The All Blacks were victorious throughout the Tri Nations in every game, but the way Australia tried to play was great for the development of rugby and for people who like to watch running rugby.
"They are coached by one of the best coaches (Robbie Deans) of all-time, and they are an incredibly difficult team to defend against.
"But we are up for the challenge. We are very determined to redress what happened last time against them and to repeat what happened the time before."
Gatland is due to announce his starting line-up on Thursday.