Star Springboks forward Duane Vermeulen on Sunday moved a step closer to emulating British and Irish Lions skipper Alun Wyn Jones and appearing in the series after a miraculous recovery from injury.
Lock Jones joined the Lions midway through the tour after defying medical opinion by speedily regaining fitness after injuring his shoulder in a warm-up win over Japan in Edinburgh.
The most-capped rugby player with 158 appearances for Wales and the Lions played in the first two Tests of a drama-filled series against the world champions.
A South Africa Rugby statement said Vermeulen joined their camp a day after they won the second Test 27-9 in Cape Town to level the series ahead of the decider this Saturday.
The 2019 Rugby World Cup winner underwent surgery after suffering an ankle injury during a domestic match two months ago and the widespread view was he would not recover in time for the series.
"Duane will join us on Sunday and will be medically assessed as soon as possible," said Springboks head coach Jacques Nienaber in a statement.
"We will never risk a player who is not 100 percent fit, but he brings experience to the squad and it will be great to have him with us."
The forward, who turned 35 last month, made a surprise return as a "water boy" for the Bulls in recent Currie Cup fixtures and coach Jake White said Vermeulen had been "actively involved in training".
- 'Bridge too far' -
"He was pushing really hard to see if he could be available for the third Test," the 2007 World Cup-winning coach told reporters. "However, I think it is probably a bridge too far.
"Duane is working hard at getting back into shape, to make himself available for selection. He spends a lot of time with our medical staff, who are helping him with his rehabilitation.
"His rehab is going really well and if everything continue to go as well as it is so far, he is probably three to four weeks away from playing."
Vermeulen excels under the high ball, an aspect of the game where the Springboks showed considerable improvement this weekend after coming off second best in the first Test.
He was desperate to face the Lions at Test level during the twilight of his career as he was not part of the national squad when the tourists last visited South Africa in 2009.
Nienaber added that the Springboks will know more on Monday about a shoulder injury sustained by 2019 World Rugby Player of the Year Pieter-Steph du Toit in the second Test.
Flanker Du Toit was hurt after a late tackle by Lions' South Africa-born winger Duhan van der Merwe and was clearly in pain before leaving the field halfway through the first half.