Experienced forward Ryan Jones is an injury doubt for Wales' November Test opener against Argentina after being sent home with a shoulder problem.
The 31-year-old had been training in Poland when the WRU confirmed that an "irritable shoulder" injury had forced him to return to Wales for scans.
Wales have already lost prop Adam Jones and flanker Dan Lydiate - two of the key figures in last season's Six Nations Grand Slam - for the series of November Tests which also includes matches against Samoa, New Zealand and Australia.
Jones, who has been in fine form for Ospreys this season, had been the favourite to replace Lydiate in the Wales starting line-up when interim head coach Rob Howley announces his team for the Pumas clash next week.
"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," read a WRU statement.
"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."