Gregor Townsend would be making "a mistake" by leaving Richie Gray out of Scotland's Rugby World Cup training camps, former prop Ryan Grant says.

The 29-year-old Toulouse lock has missed out on selection for Townsend's 44-man squad after recovering from hip surgery to help his club win the French Top 14 title this month.

But Grant, a former British and Irish Lion, says Gray's qualities are unique.

"I think we'll see Richie in and around the World Cup squad," Grant said.

"He's a specimen. As good as the other second rows are, no-one's a 6ft 10in out-and-out athlete like Richie.

"He's finding his old form again, especially watching the last 30 minutes of the Top 14 final. I think it would be a mistake not to at least bring him in."

Townsend is likely to take four locks to the World Cup in Japan this year. Gray's younger brother Jonny is vying for one of those slots, as are Glasgow Warriors colleague Scott Cummings, Edinburgh duo Ben Toolis and Grant Gilchrist, and Exeter Chiefs' Sam Skinner, who can also play on the blind-side flank.

The elder Gray, capped 65 times and a Lion with Grant in 2013, has been hampered by injuries in recent seasons, playing only one Test in over two years.

He made his comeback from a hip operation in late January and has since played 13 club matches, six as substitute.

Gray came off the bench as Toulouse beat La Rochelle in the Top 14 semi-final and Clermont in the showpiece.

"The way the game's going now, you pick guys especially for that reason, guys that can bring a huge amount of energy off the bench," Grant told BBC Radio Scotland.

"That might be the position Richie finds himself in. His brother Jonny's more of a grafter, the type of guy that does all the unseen work, you want him in for 80 minutes.

"Richie's got a bit of flair, he's got pace, he can handle the ball well, he's got good off-loads, so he might fill that position."