Wales v South Africa: Wales lose Eli Walker but door opens for Liam Williams

George North (centre) shares a joke with his team-mates during the warm-up in training (Getty Images)

The move was innocuous enough. Eli Walker, set for his Wales debut on Saturday and keen to prove a point against his more experienced team-mates, was using the pace and guile that had earned him the call-up in the first place.

Put through his paces in a training session with his sights set on the try line, the Ospreys winger jinked off his right foot, tried to accelerate out of the tackle and promptly felt a sudden twinge in his hamstring.

Ice was immediately applied to the damaged muscle but the upshot is that the international bow of a player described by Wales assistant coach Rob Howley as the "most in-form winger" in Europe as long as a year ago will have to wait for another day.

Informed of his selection on Tuesday, Walker had backed himself against the best in the world, including South Africa's Bryan Habana, as he prepared to step into the ample shoes of the injured Alex Cuthbert at the Millennium Stadium.

Instead, his place in the starting line-up will be taken by Liam Williams, the Scarlets full-back brought on to the Wales wing to deal with the anticipated aerial battle from the Springboks, while Walker's Ospreys team-mate Ashley Beck comes on to the replacements' bench.

Wales are still awaiting the results of a scan on Walker's hamstring but the general prognosis is that he will be unable to train for between 10 days to two weeks, and that there is every chance his autumnal outings are over even before they have begun.

Howley described the 21-year-old as "pretty disappointed". He added: "It's desperately disappointing. We feel so desperate and gutted for the player himself. He's added so much to our environment. I think everyone knows what ongoing problems he's been through with his back and hamstring."

Injuries are nothing new for Walker, who has had more than a year of varying problems. These began with his hamstrings last season. Although he recovered, he immediately pulled a hamstring again in his first training session back.

Walker was finally diagnosed with a bulging disc in his back, thought to have been the cause of the hamstring problems. So, he underwent the surgeon's knife to resolve the problem by shaving a section off his disc, which was affecting the nerves. It was thought the complaint was now gone before the latest injury. Of this latest setback, Howley added: "We're fearing the worst. Scan results will point us in the right direction."

For Wales, in terms of facing southern-hemisphere opposition, the only direction is up, so woeful has their record been in recent history. The last time they beat such opposition was in 2008 against Australia, while they have not defeated South Africa since 1999 when Howley himself was on the playing staff.

Should they break that pattern of poor results at the Millennium Stadium — where the roof will be closed on Saturday — the former Welsh scrum-half believes it will eclipse events from 14 years ago.

"If this side is successful this weekend this will be a better victory than back in 1999," Howley admitted, going on to suggest it would be "up there with the best" of Wales victories throughout their illustrious history.

There has, though, been no shortage of southern hemisphere success for the majority of Saturday's line-up in another guise, thanks to the recent British and Irish Lions triumph over Australia.

And this week Howley said he had seen something different from those Lions in the squad in the past week. "It's their mindset," he said. "I think in terms of the emotions of the Lions players, that has been different. It's a very positive mindset. They need to bring that to the national jersey on Saturday."