The British and Irish Lions have suffered a big blow with the loss of tour captain Alun Wyn Jones to a dislocated shoulder in their 28-10 victory over Japan in Edinburgh.
Here the PA news agency considers four alternatives who could be called upon by Warren Gatland.
Maro Itoje, England
A strong contender for the job before Jones was appointed, Itoje's claim is strengthened by his standing as the only player on this list guaranteed to start the opening Test. The Saracens lock is a force of nature and is feared by South Africa, but he has no international captaincy experience and so picking him would come with a risk attached.
Owen Farrell, England
Unlike Itoje, Farrell is an established skipper for club and country. In a recent squad poll, the versatile playmaker received the most votes when Gatland asked for a leadership group to be chosen. Ferociously competitive, he will drive standards but he is far from assured of starting in the Tests with Dan Biggar currently in pole position for the number 10 jersey.
Ken Owens, Wales
An influential figure with Wales, the veteran hooker commands instant respect on the international stage and in a nod to his standing, he took over when Jones trooped off down the Murrayfield tunnel. Gatland has a long association with the 84-cap international and took him to New Zealand four years ago, but his position is ferociously competitive with Jamie George and Luke Cowan-Dickie high-quality alternatives.
Dan Biggar, Wales
Even at this early stage with only one game played, the fly-half duties appear to be Biggar's to lose. He is a vocal presence on the pitch and can often be heard providing directions and inspiration during huddles. Another trusted lieutenant of Gatland's, he will be a central figure in South Africa but he has never captained the Ospreys or Northampton, never mind Wales or the Lions.