Wales prop Henry Thomas has been ruled out of Saturday's match against world champions South Africa at Twickenham with a foot injury.
Cardiff tighthead Keiron Assiratti has been promoted off the bench to start, with Harri O'Connor named among the replacements, the Welsh Rugby Union said in a statement issued Thursday.
The Twickenham encounter will be the Springboks' first match since they won a record fourth world title in France last year.
The South Africa fixture precedes Wales's two-test tour of Australia, with coach Warren Gatland due to finalise his 34-strong squad after the clash with the Springboks.
Gatland called former rugby league star Regan Grace into his wider squad on Thursday, with Ospreys wing Keelan Giles released after suffering a groin injury in training.
Grace, who has only played two senior games of union, could now face the Wallabies, with Wales playing Australia in Sydney on July 6 and in Melbourne seven days later, before taking on Reds on July 19.
Grace, who signed a contract with English Premiership club Bath in April, would not have been eligible to play South Africa.
That's because the fixture falls outside World Rugby's designated 'summer' international window, with English-based clubs under no obligation to release players for Wales duty.
The 27-year-old Grace scored 89 tries for Super League club St Helens during a league career that saw him feature in three Grand Final-winning teams.
Grace ruptured his Achilles tendon in August 2022 before joining Racing 92, but he did not feature for the French Top 14 rugby club after suffering an injury relapse six months later. The Welshman then joined Bath earlier this year.