Gray would not have been available to face Fiji on 2 November anyway, because that match falls outside of the usual Test window.

But the former Glasgow Warriors and Exeter Chiefs player could have faced South Africa, Portugal, and Australia, while missing just one club match.

"He's come back from a really tough injury and missed almost 18 months," Townsend added.

"But he's played every single game for Bordeaux this season and played well - in big games.

"La Rochelle at the weekend, Toulouse a couple of weeks before. He would have been in really the mix for not just our squad but our matchday 23.

"So it's disappointing both Bordeaux and Jonny think the best thing for him is to rest after two months of rugby - given he's had time off."

Ewan Johnson, Grant Gilchrist, Scott Cummings, Max Williamson, Alex Craig and Alex Samuel are Townsend's second-row options.

Gray's elder brother Richie has likely played his last game for Scotland after being omitted from the squad.

The 35-year-old has signed for Toyota Verblitz in Japan and will join at the end of November.

While the Glasgow lock was available to add to his 79 caps before departing, he has missed recent weeks with injury and Townsend, who praised Gray's stellar international career, has an eye on the future.

"We know Richie is off to Japan and won't be considered by us in the future because the Japanese season runs at the same time as the Six Nations," the head coach explained.

"So there is one eye on the future but there is also an eye on who can help us win these games. And we just felt his form did not merit that over the other guys who will be here for longer."