Wales boss Rob Howley sees "X-factor" and versatility in Liam Williams
Wales boss Rob Howley has described Liam Williams as "probably a left-wing who can play full-back" after making another switch of positions with Toulon star Leigh Halfpenny.
Many pundits view full-back as the best role for Williams, who looks set to join English and European champions Saracens next season and is rated as a British and Irish Lions certainty in New Zealand next summer.
He started in the number 15 shirt when Wales claimed a tense 33-30 victory over Japan last weekend, with Halfpenny on the wing, but those roles have been reversed for South Africa's Principality Stadium visit on Saturday.
"Liam was very disappointed with his performance (against Japan)," interim head coach Howley said.
"I spoke to him about being a connection in the back field. Liam is a very intuitive player, there is an X-factor about Liam and he has that ability to add value in the wider channels.
"But Leigh is equally important. The way we defend, Leigh Halfpenny does a lot of work on and off the ball.
"For me, at the moment, that is the best back-three (George North is the other wing). Liam is probably a left-wing who can play full-back, where I think Leigh can play both."
Captain Sam Warburton, meanwhile, has been ruled out of Wales' autumn finale after suffering a stinger injury during training on Tuesday. Stinger-type injuries normally impact on the shoulder and neck area.
Prop Gethin Jenkins will skipper the side, with Dan Lydiate, Justin Tipuric and Ross Moriarty forming Wales' back-row against the Springboks.
Centre Jamie Roberts is dropped to the bench for a second time in three Tests - Scott Williams again replaces him - while Howley recalls several players who sat out last weekend's tense victory over Japan, including North, fly-half Dan Biggar and lock Luke Charteris.
And Bath number eight Taulupe Faletau, who has played less than an hour of competitive rugby since he suffered a knee ligament injury in early September, joins Roberts among the replacements, where Sam Davies - Wales' drop-goal matchwinner against Japan - also features.
Reflecting on Warburton's absence, Howley added: "It's the same injury he had while training with Cardiff Blues before the autumn internationals.
"He felt he would get through the next 24-48 hours, but the medical staff saw him this morning and decided he wouldn't be fit."
And reflecting on 85 times-capped Roberts' omission, Howley said: "I thought Jamie did well against Japan. Jamie doesn't deserve to be dropped, but Scott played particularly well against Argentina and didn't deserve to be dropped (for Japan).
"Against Japan, when we were very direct, we were okay. International rugby is about the gain-line and the speed of ball at the breakdown. This week is about Scott doing what he did against Argentina.
"Look at the side we have picked, it's a sign of confidence from the coaches in the performance against Argentina. Dan Lydiate (for Warburton) is the only change from that."
Wales' style of play has come under the microscope this month during an autumn campaign that began with a crushing 32-8 defeat against Australia, before narrow victories were posted over Argentina and Japan.
And if they beat South Africa for only the third time in 32 meetings, it would give them a best autumn Tests winning return since they claimed three successes from four starts 14 years ago.
"We want to play, but there has to be a sensibility about when," Howley added. "We have always encouraged our squad to play because we feel we have X-factor players.
"Against Japan, we hurt ourselves. The three tries Japan scored came from us having had the ball. It was disappointing because we were in control of the ball.
"I wouldn't stop the players playing. We want to play. That is the modern game, and it's important the players and the coaches know that.
"We always look at ourselves and how we have performed. We won the game (against Japan), but the performance and the expectation of the players and coaches came up short.
"That has been discussed, because there are areas we have to work on."