Scotland have been boosted by the inclusion of Stuart Hogg and Greig Laidlaw in Gregor Townsend's first Six Nations squad, which also includes four uncapped players.
Hogg has not played since he pulled up in the warm-up to Scotland's 53-24 win over Australia on Nov. 25, but he is now in contention to start his side's championship opener against Wales on Feb. 3.
Laidlaw, meanwhile, suffered a broken leg while playing for Clermont in October and sat out all three of his country's November Tests but has been named in Townsend's 40-man squad.
Mark Bennett, Richie Gray and Duncan Taylor also return having sat out the autumn internationals, while Worcester Warriors back row David Denton -- who last played for Scotland in June 2016 -- is also recalled.
Townsend has called up Edinburgh fullback Blair Kinghorn for the first time while, D'arcy Rae, Nathan Fowles and Murray McCullum are all vying for a first international cap.
"It's a bigger squad than we originally planned -- which is largely down to the competition for places -- with a number of players having performed well in the autumn Tests and a few others putting their hands up for selection in recent weeks," Townsend said.
"We welcome Blair Kinghorn into our group for the first time, who has been in excellent form with Edinburgh this season, and also three of our most experienced players in Richie Gray, Greig Laidlaw and Scott Lawson.
"We are looking forward to working with them and the rest of the squad to ensure that we build on the momentum the players generated in 2017."
Scotland squad for the Six Nations:
Backs: Bennett, Dunbar, Grigg, Harris, Hogg, Horne, Jackson, H. Jones, L. Jones, Kinghorn, Laidlaw, Maitland, McGuigan, Price, Pyrgos, Russell, Seymour, Taylor, Fowles.
Forwards: Barclay (captain), Berghan, Bhatti, Bradbury, Denton, Du Preez, Gilchrist, J. Gray, R. Gray, Hamilton, Harley, Lawson, McCallum, McInally, Reid, Rae, Toolis, Turner, Watson, Welsh, Wilson.