There is no place for World Cup captain Gareth Thomas, as caretaker coach Nigel Davies gives some younger players a chance.
Will James also misses out - while Chris Horsman, Kevin Morgan and Dafydd James are all injured and Martyn Williams has retired.
Uncapped Llanelli full-back Morgan Stoddart is included. As well as Henson, Lee Byrne, Tom James, Rhys Thomas, Luke Charteris and Robin Sowden-Taylor also come back in.
Henson was one of the stars of Wales' 2005 Grand Slam win but did not make the World Cup after failing to re-discover his best form following injury.
Davies, who will make way for Warren Gatland after the November 24 match, will cut his squad to 24 on Sunday after the next round of Heineken Cup fixtures.
He said: "Gavin Henson is one of the players who is in the category of needing a big game this weekend to convince us he is ready to return to the international arena.
"He has been showing encouraging signs for the Ospreys, and it will be a tough test for him at Gloucester playing against Mike Tindall and Anthony Allen.
"We need him somewhere near the peak of his powers if we are to get the best out of him - and that is what we will be looking for.
"I've spoken to Gareth Thomas about our selection policy. Although he hasn't ruled himself out of the international reckoning, he has stated publicly that it is perhaps time for younger players to come through and make an impact.
"In this instance, I would tend to agree with him - especially in the light of the performances put in by Stoddart, Lee Byrne and Tom James so far this season.
"This could be a chance for us to have a look at how these talented young players cope with the pressure of performing on the international stage.
"That said, we still need a certain amount of experience to take on a team of the calibre of South Africa. With Martyn Williams retiring, we felt we needed to retain the unique talents and physicality of Colin Charvis within the group."
Wales preliminary squad for Prince William Cup match against South Africa on November 24:
Backs: L Byrne (Ospreys), M Stoddart (Llanelli), M Jones (Llanelli), S Williams (Ospreys), T James (Cardiff), T Shanklin (Cardiff), J Robinson (Cardiff), G Henson (Ospreys), S Parker (Ospreys), S Jones (Llanelli), J Hook (Ospreys), C Sweeney (Newport Gwent), M Phillips (Ospreys), D Peel (Llanelli), G Cooper (Gloucester).
Forwards: J Thomas (Ospreys), A Popham (Llanelli), C Charvis (Newport Gwent), R Sowden-Taylor (Cardiff), A-W Jones (Ospreys), I Evans (Ospreys), M Owen (Newport Gwent), L Charteris (Newport Gwent), I Gough (Ospreys), R Thomas (Newport Gwent), A Jones (Ospreys), H Bennett (Ospreys), M Rees (Llanelli), T R Thomas (Cardiff), G Jenkins (Cardiff, capt), D Jones (Ospreys).