Lock Bradley Davies will miss Wales' two-Test tour to South Africa in June because of a hamstring injury.
The Cardiff Blues lock, 27, who is heading to Wasps, suffered the problem in training and has undergone surgery.
Meanwhile, Racing Metro flanker Dan Lydiate is out of Friday's Wales Probables v Possibles trial in Swansea.
But Lydiate's hamstring strain is not expected to rule him out of the tour, which starts with a warm-up against Eastern Province Kings on 10 June.
Wales face the Kings in Port Elizabeth followed by the Springboks in Durban on Saturday, 14 June and again in Nelspruit a week later.
In Davies' absence, Alun Wyn Jones and Luke Charteris have been picked at lock for the Probables, while Jake Ball partners Ian Evans in the second-row for the Possibles side at the Liberty Stadium on Friday.
Probables (coach Rob Howley):
Liam Williams (Scarlets); Alex Cuthbert (Cardiff Blues), Jonathan Davies (Scarlets), Jamie Roberts (Racing Metro), Jordan Williams (Scarlets); Dan Biggar (Ospreys), Mike Phillips (Racing Metro); Gethin Jenkins (Cardiff Blues), Ken Owens (Scarlets), Adam Jones (Ospreys), Alun Wyn Jones (Capt) (Ospreys), Luke Charteris (Perpignan), Josh Turnbull (Scarlets), Aaron Shingler (Scarlets), Taulupe Faletau (Newport Gwent Dragons).
Replacements: Scott Baldwin (Ospreys), Aaron Jarvis (Ospreys), Samson Lee (Scarlets), Lewis Evans (Newport Gwent Dragons), Josh Navidi (Cardiff Blues), Rhodri Williams (Scarlets), Sam Davies (Ospreys), Dafydd Hewitt (Cardiff Blues).
Possibles (coach Robin McBryde):
Dan Fish (Cardiff Blues); Kristian Phillips (Scarlets), Cory Allen (Cardiff Blues), Steven Shingler (Scarlets), Harry Robinson (Cardiff Blues); James Hook (Perpignan), Gareth Davies (Scarlets); Rob Evans (Scarlets), Matthew Rees (Capt) (Cardiff Blues), Rhodri Jones (Scarlets), Jake Ball (Scarlets), Ian Evans (Ospreys), Andrew Coombs (Newport Gwent Dragons), Ellis Jenkins (Cardiff Blues), Dan Baker (Ospreys).
Replacements: Kristian Dacey (Cardiff Blues), Owen Evans (Newport Gwent Dragons), Scott Andrews (Cardiff Blues), Macauley Cook (Cardiff Blues), James Davies (Scarlets), Lloyd Williams (Cardiff Blues), Matthew Morgan (Ospreys), Jonathan Spratt (Ospreys).