Jones disappointed to leave camp
Ryan Jones is "bitterly, bitterly disappointed" to have made an early exit from Wales' pre-autumn Tests training camp in Poland.
The former Wales captain has handed interim head coach Rob Howley an injury scare just 10 days before the autumn opener against Argentina.
Howley had already lost star forwards Adam Jones and Dan Lydiate from a demanding series that also features appointments with Samoa, New Zealand and Australia.
Vastly-experienced Jones, 31, is viewed as an obvious blindside flanker replacement for Lydiate.
But the Ospreys back-row player, who has won 67 caps, left snowy Spala today to undergo scans on what the Welsh Rugby Union said was "an irritable shoulder".
"Bitterly bitterly disappointed to be heading home, desperate to be a part of this Autumn series!" Jones said on Twitter.
Howley is due to announce his team for the Pumas clash tomorrow week. Jones, 31, headed to Spala with the Wales squad three days ago, and the WRU said today he had been managing a shoulder problem prior to that.
A WRU statement read: "The decision to send Jones home at this time is based on a preference for the facilities available in Wales to accommodate the necessary investigations and give the player the most optimal management plan for his injury.
"Jones remains a full member of the squad and further details of his problem and any repercussions for selection, if at all, will become apparent once the proper investigations have been undertaken."
Adam Jones was ruled out of the autumn games last week due to a knee problem that could require more than two months' rehabilitation.
And Lydiate suffered a serious ankle injury playing for Newport Gwent Dragons earlier this season.
In addition to missing the autumn schedule, it is unlikely Lydiate will play any part in Wales' Six Nations title defence, although he is expected to regain full fitness ahead of next summer's British and Irish Lions tour to Australia.
Matthew Rees, meanwhile, has backed one of Wales' young props to make an impression this autumn as the Six Nations champions prepare for life without Adam Jones.
While Howley could consider switching Bath loosehead Paul James across the scrum as Jones' replacement, it is probable that either Aaron Jarvis, Scott Andrews or Samson Lee will start against the Pumas.
Uncapped Lee, although not yet officially added to Wales' autumn squad, is currently part of preparations in Poland.
And his fellow international rookie Jarvis has impressed with a series of consistent displays for the Ospreys that underpinned his Wales call-up.
"We have props who can play both sides of the scrum, with Paul James and Gethin Jenkins both able to move over, and it will be up to the coaches when it comes to selection," hooker and former Wales captain Rees said.
"But I can certainly see one of these youngsters coming through and getting to the next level over the next three or four weeks.
"Adam is a loss, but we have got three pretty good players there waiting in the wings at the moment, and the challenge for them now is to kick on and impress the coaches and take their chance when it comes.
"The only thing they may lack is experience at international level, but there is no better place for them to get that than in this November series when you look at the fixture list."
The Argentina clash will be Wales' first Test match since they lost a summer series 3-0 to Australia Down Under, although the last two defeats were by a combined total of just three points.
"We were all disappointed with how things went in Australia, but we have the opportunity now to climb that ladder again and get up the world rankings to where we feel we belong," Rees added.
"We feel that we are close, within touching distance.
"If we continue to prepare well and make sure we are competitive against these top teams, keep the errors down and maybe be just be a bit smarter, then we know the big wins will come.
"We are not far away. We know we can do it, and it all starts against the Pumas in 10 days' time."