Wales centre Roberts will join his international colleagues Mike Phillips, James Hook, Gethin Jenkins and Luke Charteris across the English Channel next season after rejecting a new deal from Cardiff Blues.
The current France-based quartet missed Wales' critical pre-autumn training camp in Poland last week due to club commitments.
While Toulon prop Jenkins still starts against Millennium Stadium visitors Argentina on Saturday, Phillips and Hook are on the bench and Charteris plays for Perpignan this weekend after a deal was struck between his club and Welsh Rugby Union that would see him freed in return to face Australia on December 1.
"It is obviously a difficult scenario for us," Wales skills coach Neil Jenkins said today.
"We want our best players playing in Wales as often as possible.
"Jamie has made a decision that he won't be with the Blues. The most important thing from our point of view is that whenever he does go, he gets full release and he can come to these pre-autumn and pre-Six Nations training camps.
"If that is the case, Jamie will be a full part of this Wales squad going forward.
"He is an outstanding player. He has been outstanding for Wales and the British and Irish Lions. He leads from the front.
"I am sure Jamie wants to be a big part of this Wales set-up going forward."
Although Roberts' destination next term has yet to be announced, Press Association Sport understands it will be wealthy Parisians Racing Metro, whose most recent signing was former Bath and England back Olly Barkley.
Speaking two days ago, 26-year-old Roberts underlined the huge importance to him of playing for Wales, which suggests securing the required contractual clauses will be high on his agenda.
"Missing the last three (Wales) games has made it that more important to me," said Roberts, who has now fully recovered from a serious knee injury and returns to the Test arena this weekend.
"It's true - you don't know what you have got until it has gone. When you miss games you are chomping at the bit to get back in the team.
"When you don't play, you miss that buzz. When you wear the red shirt of Wales you know how many people you are representing and how many incredible players have worn the shirt before you.
"That is pretty special, and that is what you miss. Running out at the Millennium Stadium in front of 70,000 Welsh fans is indescribable, really."
Blues chairman Peter Thomas, meanwhile, has issued a stark warning that Welsh rugby's exodus of star players will continue without increased funding.
The Blues have claimed that 44 times-capped Roberts rejected a deal with them that would have made him among the United Kingdom's highest-paid players.
Wales interim head coach Rob Howley has already delivered a blunt message about players' international prospects if they opt to move outside the Principality.
Thomas said: "We have invested a lot of time, money and effort developing Jamie as a rugby player from an early age after identifying him as a star of the future.
"We have stuck by him through thick and thin and supported him during last season when he only completed two matches for the Blues because of his knee injury and international duties, playing 15 matches for Wales.
"It is impossible for the Welsh regions to compete with the kind of money that is on offer from other clubs in other countries.
"The time has come that the Welsh benefactors should not be responsible for funding the professional game.
"The chairman of the regions can guide companies, but if we want to keep Jamie Roberts and other international players in Wales then the governing body has to intervene.
"The player drain out of Wales, which has a negative impact on the Welsh regions and the national team, will only continue without increased funding from the governing body."
One way forward might be for the WRU to secure top players on central contracts, but WRU group chief executive Roger Lewis recently claimed that Wales' four professional regions - the Blues, Ospreys, Scarlets and Newport Gwent Dragons - rejected that idea.
Roberts, who is currently in the final academic year of studies to become a doctor, made his Wales debut in 2008 and has become a pivotal player during the Warren Gatland coaching era.
He returned to playing in September after being sidelined for six months through injury. During that spell out of the game he missed Wales' three-Test Australia tour last summer.
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