Scotland have called up four players to their Six Nations squad after injuries to several players including first-choice open-side flanker Hamish Watson.
Edinburgh's Watson has dropped out of the squad while he recovers from a suspected fracture to his hand.
Glasgow trio Sam Johnson (concussion), Jonny Gray (shoulder) and Ryan Wilson (shoulder) will remain in camp.
Uncapped back-row duo Luke Crosbie and Matt Smith, plus centre Alex Dunbar and lock Rob Harley, have joined the squad.
Watson's absence is a major blow given the consistent excellence of his performances over the past two years, starting 11 of Scotland's last 12 Tests.
His former Edinburgh team-mate John Hardie, now at Newcastle, and another Falcons flanker, Gary Graham, were the other open-sides included in the original 39-man squad, with Edinburgh club-mate Jamie Ritchie, who can play on both flanks, another option for Scotland's opener against Italy on 2 February.
Edinburgh's Crosbie, 21, and Glasgow's Smith, 22, will provide additional cover.
With Johnson undergoing head injury assessment protocols, Warriors team-mate Alex Dunbar, who has 31 caps, is recalled after being left out of the original squad.
The experienced Harley, who won the last of his 20 caps in June 2017, is also added to the party as second-row cover, with Edinburgh duo Ben Toolis and Grant Gilchrist, Exeter's Sam Skinner and Glasgow's Tim Swinson already competing for starting spots.
Revised Scotland squad:
Props: Alex Allan (Glasgow Warriors), Allan Dell (Edinburgh), Jamie Bhatti (Glasgow Warriors); Simon Berghan (Edinburgh), Willem Nel (Edinburgh), D'Arcy Rae (Glasgow Warriors). Hookers: Dave Cherry (Edinburgh), Jake Kerr (Leicester Tigers), Stuart McInally (Edinburgh), Grant Stewart (Glasgow Warriors). Locks: Grant Gilchrist (Edinburgh), Jonny Gray (Glasgow Warriors) Rob Harley (Glasgow Warriors), Sam Skinner (Exeter Chiefs), Tim Swinson (Glasgow Warriors), Ben Toolis (Edinburgh). Back row: Adam Ashe (Glasgow Warriors), Luke Crosbie (Edinburgh), Gary Graham (Newcastle), John Hardie (Newcastle), Jamie Ritchie (Edinburgh), Matt Smith (Glasgow Warriors), Josh Strauss (Sale Sharks), Ryan Wilson (Glasgow Warriors).
Back three: Darcy Graham (Edinburgh), Stuart Hogg (Glasgow Warriors), Lee Jones (Glasgow Warriors), Blair Kinghorn (Edinburgh), Sean Maitland (Saracens), Tommy Seymour (Glasgow Warriors). Centres: Chris Dean (Edinburgh), Alex Dunbar (Glasgow Warriors), Nick Grigg (Glasgow Warriors), Chris Harris (Newcastle Falcons), Peter Horne (Glasgow Warriors), Sam Johnson (Glasgow Warriors), Huw Jones (Glasgow Warriors). Fly-halves: Adam Hastings (Glasgow Warriors), Finn Russell (Racing 92). Scrum-halves: George Horne (Glasgow Warriors), Greig Laidlaw (Clermont Auvergne - captain), Ali Price (Glasgow Warriors).