Wales could be without their 'foreign' based players for their 3 December showdown against Australia in Cardiff.
Mike Phillips, James Hook and Lee Byrne play in France and Craig Mitchell, Andy Powell and Dwayne Peel are in England.
Non-Welsh clubs do not have to release their players for games outside the International Rugby Board window, unless individual contracts allow.
Wales' regions have agreed to release their players for the repeat of the Rugby World Cup third-place play-off.
Scrum-half Phillips plays for Bayonne and his side face Agen in the French Top 14 on Saturday, 3 December.
Hook's Perpignan are at Lyon on that day while full-back Byrne is to play for Clermont Auvergne in a home game with Castres.
Back-row forward Powell and scrum-half Peel are likely to be with Sale Sharks at Bath in the English Premiership, while prop Mitchell could be part of Exeter's squad when they host Worcester Warriors.
Former Ospreys number nine Phillips earned plaudits for his performances during Wales' World Cup campaign.
Hook and Byrne, who also left the Liberty Stadium region this summer, had mixed fortunes as Wales finished fourth in New Zealand.
Cardiff Blues back Leigh Halfpenny kept Byrne out of the full-back jersey, apart from one pool game against Namibia, while Hook saw Scarlets fly-half Rhys Priestland make a huge success of his number 10 chance.
But Priestland missed Wales' final two games after damaging a shoulder in the 22-10 quarter-final win over Ireland.
Hook started at fly-half in the 9-8 semi-final defeat by France and the third-place play-off defeat to Australia, but missed crucial kicks in both games.
Powell came off the bench four times at the World Cup, Mitchell missed out apart from facing Namibia at the pool stages, while Peel was not picked in coach Warren Gatland's World Cup squad.
