The 32-year-old, who previously spent three years at Scotstoun and made 32 appearances, was most recently with Newcastle Falcons and will bolster Franco Smith’s options at lock – especially with Du Preez out for the foreseeable future. The South African injured his knee in training and will be sidelined for several months and with fellow second rows Scott Cummings and Richie Gray to be managed carefully following time away with Scotland at the World Cup, Glasgow’s only other senior options in that position are Alex Samuel and Max Williamson.

“The opportunity to come back to Glasgow was an easy one,” said Peterson, who has 39 caps for the USA. “Tess [his wife] and I made a lot of lifelong friends during our first spell here and it’s a place and a club that hold a lot of fond memories for us, so the decision was pretty straightforward when I got asked to come back for the next couple of months.

“It all came about pretty quickly really. I’m thankful that it all got sorted out pretty quickly – the biggest obstacle was the multiple time zones we were dealing with! I was back in Australia and then over in Salt Lake City with the USA squad, but we got it over the line.

Greg Peterson was most recently at Newcastle Falcons.

“I definitely feel like I’ve developed as a player and a person since I was last here. I’ve had two kids since then, so I’ve learnt a lot of patience for sure! I’ve learnt a huge amount from both the Top14 and Premiership, too, and matured as a second-rower, so hopefully I can come back, help the young boys we’ve got here and help us start the season off strongly.”

Head coach Smith added: “With JP starting his rehabilitation and Scott and Richie’s return to be managed after a tough training camp and Rugby World Cup for Scotland, we’re happy to be able to add someone of Greg’s experience and quality to strengthen our squad for the start of the season.

We’ve been really pleased with how Max and Alex, and Ruaraidh Hart, have shown up in our pre-season games, as developing our young talents is key not only for us, but for Scottish rugby overall. We want to make sure that they are given their chances when they are ready as our depth of squad will be important, so adding Greg gives us an additional option in the second-row and we’re pleased to welcome him into our group at Scotstoun.”

Glasgow Warriors sign Greg Peterson after being rocked by JP du Preez injury blow