Gavin Henson has been included in the Probables squad for the Wales trial match on 30 May in Swansea.
The utility back, 32, has enjoyed something of a resurgence at Bath this season, but won the last of his 33 Wales caps in a World Cup warm-up match against England in August 2011.
Lock Alun Wyn Jones will lead the Probables, with hooker Matthew Rees captaining the Possibles.
Leicester fly-half Owen Williams has been named in the Possibles squad.
However, the England-based players selected may not be available for the game at the Liberty Stadium.
A spokesperson for England's Premiership clubs has said that because the game is not a Test match they do not have to release non-England players.
The Welsh Rugby Union hopes to reach an agreement with Premiership Rugby, but the trial match takes place the day before the Aviva Premiership final.
There has been no definite indication yet whether Welsh-qualified players at French clubs will be available for the trial match, the first to be held by Wales for 14 years.
However, BBC Wales Sport has learned Perpignan lock Luke Charteris will be available.
The trial match will help decide who is included in Warren Gatland's final squad for the two-Test tour to South Africa in June.
Probables head coach Rob Howley has named a squad with two uncapped players in Dragons prop Owen Evans and Ospreys' Sam Davies as well as 19 of the recent Six Nations squad.
The return of Henson into the Wales reckoning marks the end of a tumultuous period since leaving the Ospreys in 2009.
The Bridgend product, who helped Wales to Grand Slams in 2005 and 2008, has played for Saracens, Toulon, Cardiff Blues and London Welsh before arriving at the Recreation Ground last season.
In that period he endured long-term injuries, dabbled with reality television and was involved in several off-field misdemeanours.
Possibles head coach Robin McBryde has selected 10 uncapped players in his 26-man squad, including some exciting rising talent at half-back.
Scarlets pair Gareth Davies and Steven Shingler are named along with Leicester fly-half Williams and Osprey Matthew Morgan, whose regional number eight team-mate Dan Baker is also included.
The likes of James Hook, Ian Evans, Bradley Davies and Paul James add an experienced backbone to the Possibles.
Wales will play a warm-up game against Eastern Province Kings on 10 June before facing the Springboks in back-to-back Tests on 14 and 21 June.
Probables Squad (coach Rob Howley):
Forwards: Gethin Jenkins (Cardiff Blues), Owen Evans (Dragons), Rhys Gill (Saracens), Ken Owens (Scarlets), Scott Baldwin (Ospreys), Adam Jones (Ospreys), Samson Lee (Scarlets), Alun Wyn Jones (Ospreys) (Captain), Luke Charteris (Perpignan), Jake Ball (Scarlets), Ryan Jones (Bristol), Aaron Shingler (Scarlets), Josh Navidi (Blues), Dan Lydiate (Racing Metro), Taulupe Faletau (Dragons).
Backs: Rhodri Williams (Scarlets), Mike Phillips (Racing Metro), Dan Biggar (Ospreys), Sam Davies (Ospreys), Jon Davies (Scarlets), Jamie Roberts (Racing Metro), Gavin Henson (Bath), Alex Cuthbert (Cardiff Blues), George North (Northampton), Hallam Amos (Dragons), Liam Williams (Scarlets).
Possibles Squad (coach Robin McBryde):
Forwards: Paul James (Bath), Phil Price (Dragons), Rob Evans (Scarlets), Matthew Rees (Blues), Kristian Dacey (Blues), Rhodri Jones (Scarlets), Scott Andrews (Blues), Aaron Jarvis (Ospreys), Bradley Davies (Blues), Andrew Coombs (Dragons), Ian Evans (Ospreys), Macauley Cook (Blues), Josh Turnbull (Scarlets), James Davies (Scarlets), Dan Baker (Ospreys).
Backs: Gareth Davies (Scarlets), Lloyd Williams (Blues), James Hook (Perpignan), Matthew Morgan (Ospreys), Harry Robinson (Blues), Owen Williams (Leicester), Steven Shingler (Scarlets), Cory Allen (Blues), Jonathan Spratt (Ospreys), Tom Prydie (Dragons), Jordan Williams (Scarlets).