Jamie Roberts (r): Back after knee surgery

Roberts lines up against Millennium Stadium opponents Argentina, ending a hectic week that saw him celebrate his 26th birthday on the same day Cardiff Blues announced he had rejected a deal to remain with them next season.

While Roberts' club rugby future now looks certain to be in France with wealthy Parisians Racing Metro, his immediate aims revolve around the international arena.

The midfield powerhouse has not played for Wales since they clinched a second Six Nations title and Grand Slam of Warren Gatland's coaching reign last March.

A knee injury, subsequent surgery and rehabilitation meant Roberts missed the three-Test summer tour to Australia, when Wales lost two games by a combined margin of three points.

"When you miss a campaign, a summer tour, it makes you appreciate it more and more. I can't wait for Saturday," Roberts said.

"It has been a very long six months. My last memories I have in a red shirt are of walking around the pitch after the France game with the Six Nations trophy.

"Anyone who has had a cruciate knee reconstruction will tell you they are not very nice. You go to hell and back with the rehabilitation. It's tough.

"But rugby is tough. You have injuries and setbacks and you have to climb the mountain again. When you have a serious injury you start again from the bottom.

"I can picture what the changing rooms must have been like in Australia and I am sure the boys who were out there will use it as motivation for this autumn series.

"To go that close to a team like Australia in their own back yard will hurt the guys and hopefully we can do the job this autumn."

Roberts will win his 45th cap in a side shorn of injured quartet Jonathan Davies, Adam Jones, Dan Lydiate and Ryan Jones, while interim head coach Rob Howley has opted to put France-based stars Mike Phillips and James Hook on the bench.

And the home side's degree of difficulty is increased by the fact that, unlike in previous years, Argentina have arrived on British soil following intensive preparation provided by their debut Rugby Championship campaign which featured home and away appointments with New Zealand, Australia and South Africa.

"Argentina pose a huge threat," Roberts added. "They are the most improved international team in world rugby over the last year.

"Their players will be looking to come to Wales and spoil the party. They will be raring to go and we are prepared for it."

As ever when Argentina provide the opposition, Wales know they must at least establish parity up-front and absorb the Pumas' traditional forward power.

Debutant prop Aaron Jarvis has a key role to play in that respect, together with flanker Josh Turnbull, whose tackling and ball-carrying prowess are two of the reasons he has been asked to fill a blindside berth vacated by Lydiate and Jones.

"Argentina have a pack of forwards who are renowned for being physical and tough," Wales hooker Matthew Rees said.

"There are a few personnel changes with (Mario) Ledesma and (Rodrigo) Roncero retiring, but it's pretty much inbred in them at scrum-time, so it's important we get our house in order to make sure we are able to do what we want to do and come out on top.

"If you give Argentina an inch they will take it and it will be a tough day at the office. It is up to us to focus on what we are going to bring to the game and make sure we deliver.

"It is our opening game of the autumn series and it's important we get off to a winning start. Whether it is by one point or by five, or whatever, we will take it."

With the All Blacks and Wallabies looming after next week's clash against Samoa, Wales know their autumn campaign will be judged on the outcome of those latter two fixtures.

Australia represent a more realistic victory prospect than the world champions on current form, and Rees admits that summer tour memories from Down Under have not disappeared.

"We went so close out in Australia in the summer - we lost those games ourselves," he added.

"The next level for us as a team is to close the game down in the last 15 minutes if we are ahead on the scoreboard."