Wales debutant Cory Allen has suffered a suspected dislocated shoulder during his team's victory over Argentina on Saturday.
The 20-year-old is now expected to miss Wales's next two matches against Tonga and Australia.
Allen's midfield partner Scott Williams is also likely to be sidelined after picking up a toe ligament problem at Cardiff's Millennium Stadium.
Wales play host to Tonga next weekend before they entertain the Wallabies on November 30.