Porthen, a former Junior Springbok captain, has had a meteoric rise this season but has still only played a handful of games for the Stormers in the United Rugby Championship ahead of his international debut.
“I don’t know him that well personally, but Daan has worked with him a lot and he comes through our Elite Player Development structures,” Erasmus said. “What I’ve seen of him when he’s playing for the Stormers is that he’s a nice, natural athlete.
“I haven’t coached him or worked with him a lot, I’ve maybe said a hundred words to him, but he understands why we’re starting him and who he’s starting with.
“He seems to be quite level-headed, obviously excited, but he will be nervous. That’s why there’s a team around him to give him the best chance of performing.”
Porthen, 21, will scrum with Rugby World Cup winners Malcolm Marx (hooker) and Ox Nche (prop) in what is otherwise a vastly experienced front row.
They are up against a Japanese forward pack that held Australia well this past weekend but is not known for pushing teams backwards in the scrum.
Erasmus says age is no factor for him and that if a player is good enough, that is all that matters.
“We played Canan Moodie when he was 18 against Australia away from home, and he scored the match-winning try against Marika Koroibete after we’d lost the first Test,” Erasmus said. “A guy like (wing) Ethan (Hooker) is 22.”
Another major move for the weekend sees Cheslin Kolbe make a rare start at full-back after a hamstring injury picked up by Damian Willemse for the Stormers this past weekend.
“I think he’s started two games at full-back. The last one, I think, was in 2022 in Ireland,” Erasmus said. “But obviously, he’s moved there for us in games before, and he’s played there a lot in the French Top 14.
“We could’ve possibly moved Handre (Pollard) or Manie (Libbok) to 10 and shifted Sacha (Feinberg-Mngomezulu) to 15, but we felt we needed a little more continuity with Sacha finding his feet at Test match level against different opposition.
“With Kurt-Lee (Arendse) being back and Ethan playing well, we had the luxury of giving Cheslin a chance there.”
The Japan game is the start of a five-match tour for the Springboks, who also play France, Italy, Ireland, and Wales.
