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Glasgow and Scotland flanker Rob Harley is set to miss the 2016 Six Nations Championship due to the thumb injury he suffered in last weekend's win over Scarlets.

The back-row forward has been ruled out for up to three months following the injury suffered in the 9-6 European Champions Cup win at Parc y Scarlets.

It is a cruel blow for the 25-year-old just five months after he was surprisingly left out of Scotland's World Cup squad.

Warriors head coach Gregor Townsend had been thrilled with how Harley responded to the disappointment of missing the tournament, insisting he had done enough to earn a recall by Dark Blues boss Vern Cotter ahead of their Six Nations opener with the Auld Enemy on February 6.

Townsend said: "Rob is going to be out for up to three months which is another blow for him because I think he's been in great form.

"He played during the Six Nations last year and his form this season merited him at least being in the mix this season.

"There is a lot of competition for the back-row but the way Rob was playing he certainly should have been considered.

"The good news is that he was operated on down in Swansea and was able to come back up on the plane with us. He knows the timescale on his recovery now but he was cracking jokes in our team meeting yesterday so he seems to be in good spirits."

Harley's hand wound now counts him out of Sunday's 1872 Cup match with rivals Edinburgh. The Murrayfield clash -- which doubles as a Guinness Pro12 fixture -- is the first leg of the annual festive double header, won last year by Alan Solomons' side.

Townsend is eager to wrest the trophy back but will also have to do without Mike Blair and Alex Dunbar, with concussion and hamstring issues likely to rule out both men in the short-term.

However, the coach has been able to name a strong starting XV as he plots a course for the league's top four.

Stuart Hogg returns at full-back, while Tommy Seymour starts on the wing in place of veteran Scotland international Sean Lamont.

Peter Horne comes in for Dunbar at inside centre, while scrum-half Blair is replaced by Grayson Hart.

There are four changes in the pack as prop Ryan Grant starts ahead of Alex Allan, while a new-look back-row sees flankers Ryan Wilson and Chris Fusaro replace Harley and Simone Favaro, with Adam Ashe starting at number eight ahead of Josh Strauss.