Wales coach Warren Gatland will run the rule over several uncapped players in this week's senior 'trial' match.
Coaches Rob Howley and Robyn McBride have confirmed their line-ups for Friday's game between the 'Probables' and 'Possibles' at Swansea's Liberty Stadium.
Howley has included one uncapped player in Scarlets wing Jordan Williams in his XV with three more on the bench in Newport Gwent Dragons back-row Lewis Evans, Ospreys' Sam Davies and Cardiff Blues centre Dafydd Hewitt.
McBryde's 'Possibles' side features two uncapped players in the pack - Scarlets prop Rob Evans and former Wales Under-20 skipper Ellis Jenkins.
The match will be a final hit-out for the players from Welsh regions before Gatland names his squad for the two-Test tour of South Africa next month.
A number of players based with English clubs were included in the initial squads for the trial game but they have not been released to play, including George North of Aviva Premiership finalists Northampton and Bath's Gavin Henson.
Several experienced players, most notably Wales captain Sam Warburton, Leigh Halfpenny, Scott Williams and Rhys Priestland, will not be involved this summer because of injury.
Howley, who is Gatland's backs coach, said: "Friday is a huge opportunity for players and a chance for us to see them go up against each other for the Wales jersey.
"It's something we haven't been able to do for the last decade, but it will be a big night for the players, we want to see them in a pressured environment and that's what we will get on Friday."
Gatland is due to name his 31-man squad for South Africa after the trial match.
Probables: L Williams (Scarlets); A Cuthbert (Cardiff Blues), J Davies (Scarlets), J Roberts (Racing Metro), J Williams (Scarlets); D Biggar (Ospreys), M Phillips (Racing Metro); G Jenkins (Cardiff Blues), K Owens (Scarlets), A Jones (Ospreys), A-W Jones (Ospreys, capt), L Charteris (Perpignan), J Turnbull (Scarlets), A Shingler (Scarlets), T Faletau (Newport Gwent Dragons).
Replacements: S Baldwin (Ospreys), A Jarvis (Ospreys), S Lee (Scarlets), L Evans (Newport Gwent Dragons), J Navidi (Cardiff Blues), R Williams (Scarlets), S Davies (Ospreys), D Hewitt (Cardiff Blues).
Possibles: D Fish (Cardiff Blues); K Phillips (Scarlets), C Allen (Cardiff Blues), S Shingler (Scarlets), H Robinson (Cardiff Blues); J Hook (Perpignan), G Davies (Scarlets); R Evans (Scarlets), M Rees (Cardiff Blues, capt), R Jones (Scarlets), J Ball (Scarlets), I Evans (Ospreys), A Coombs (Newport Gwent Dragons), E Jenkins (Cardiff Blues), D Baker (Ospreys).
Replacements: K Dacey (Cardiff Blues), O Evans (Newport Gwent Dragons), S Andrews (Cardiff Blues), M Cook (Cardiff Blues), J Davies (Scarlets), L Williams (Cardiff Blues), M Morgan (Ospreys), J Spratt (Ospreys).