An ankle injury that curtailed the end of his solitary season with Perpignan in France and ruled him out of Scotland’s Nations Championship series continues to trouble the now 30-year-old. But Glasgow defence coach Scott Forrest believes it won’t be long before the former Edinburgh back-rower is back making an impact for both (new) club and country.

“Listen, I think Jamie’s obviously, for probably personal reasons, family reasons, made the decision to come back to Scotland,” he said. “And we’re delighted to have him here. He’s a top-quality international player. We’re delighted to have him involved. I think if he was fit over the summer, he may well have been named in that Scotland squad. We fully expect him to be involved if he’s fit. One, involved with us, but also to be involved with Scotland in the second part of the Nations Championship and the Six Nations going forward.”

Van der Merwe’s arrival in Scotland has been delayed due to Pumas’ involvement in the Currie Cup. He started at open-side in his team’s 38-14 loss to Griquas last weekend, was shown an early yellow card for head-on-head contact before being replaced after 52 minutes. Pumas’ next match is against the Cheetahs on Saturday.

“Ruwald’s still playing Currie Cup so he’s not in the building now,” added Forrest. “But again, he’s playing right now, which is good. We’ve not got an exact date [on his arrival] because it will just depend on if he gets to the play-offs. But again, by the time he comes in, everyone’s going to be back in the building. So he’ll have a bit of time just to get up to speed with how we do things here.”

There will likely be two other Glasgow debutants in the weeks ahead. Neither Tavi Tuipulotu nor Charlie Savala played a minute of competitive rugby last season after signing last summer, the pair sidelined with serious injuries for the duration of the campaign. Both, though, are now fit and showing up well in pre-season. Tuipulotu, Sione’s youngest brother, is expected to provide a third option at hooker behind Gregor Hiddleston and Seb Stephen, while Savala will compete with Dan Lancaster and Matt Urwin for the 10 shirt.

“They are like new signings,” added Forrest. “It’s like having two new players in the building. Physically, they look unbelievable in terms of the work that they’ve put in. That’s tough, to be out for a full year. But the work that both Tavi and Sav have put in over the whole of last season and the off-season, that’s been really encouraging because they’re training really well. Tavi especially, just some of the movement he had on the pitch today, especially from a defensive side of the game – he was excellent in training. So there’s a bit of an excitement there around seeing both of them play.”

After two weeks at Burnbrae, the squad is now in a “reset week” where they are expected to work on training programmes in their own time. The Scotland internationals will rejoin the others from Monday but it will be those who are already deep into their preparations that will take to the field to play the Newcastle Red Bulls at Kingston Park a week on Saturday (September 5) and Bath at Old Anniesland on September 18.

“When we come back in, which is right at the end of August, start of September, everyone will be back in the building then,” conformed Forrest. “So those boys that were on tour with Scotland, they’ve got another [week]. But, to be honest, we’ve seen most of them because that’s all of them are back in doing their own individual running and most of them are using this as a training base.

“The group that’s been in training, that’s the group that’s going to play against Newcastle. We’ve already started those conversations with the boys around what that team will look like for Newcastle, just to get people ready for it. And that’s probably going to be the core of the team that will play against Bath as well. Part of it is we want to give these guys an opportunity. They’ve worked hard over the off-season, they’ve come back in, they’ve trained really well.

“And that first league game [away to Munster on September 26], about a month or so away, that’s when we’ll start to blend the team a little bit which is exciting because you’ve got a lot of good young boys there that have got an opportunity to put their hand up. This is their main window to go and do that. The Scotland boys, because of what they’ve done over the summer, playing those Test matches, there’s no real need for them to play in the pre-season games. They’ve had their chance to reset physically and mentally. Now they’re building back up. And hopefully the plan works and we’re ready to hit the ground running against Munster.”