Cardiff - Wales lock Bradley Davies has been ruled out of next week's November series climax against Australia in Cardiff, the Welsh Rugby Union announced on Thursday.
Davies suffered a shoulder injury during last weekend's 40-6 victory over Argentina and had already been ruled out of Friday's match against Tonga at Cardiff's Millennium Stadium.
Now the WRU has confirmed Davies has had an operation.
"After medical assessments, he has undergone surgical intervention," the WRU said.
"He has been released back to Cardiff Blues alongside regional team-mate Cory Allen."
Davies, who started this month against South Africa and Argentina, joins Allen, Jonathan Davies, Adam Jones, Eli Walker and Rhys Patchell on the sidelines after all six players suffered injuries this month.
Wales had already lost British and Irish Lions backs Jamie Roberts and Alex Cuthbert, who both suffered ankle injuries prior to the end-of-year Tests.
Luke Charteris, one of the starting locks against Tonga, now appears to be first in line to partner Alun Wyn Jones in the Wales second row against the Wallabies on November 30.