Finn Russell returns to the Scotland squad after missing the Six Nations matches in February and March for a breach of team protocol.
The star fly-half is joined by uncapped trio Scott Steele, Oli Kebble and Duhan van der Merwe, with the latter two qualifying on residency grounds.
Back row Blair Cowan, 34, is selected by head coach Gregor Townsend four-and-a-half years after his last cap.
Experienced Glasgow Warriors lock Richie Gray also makes the 40-man pool.
Gray, with 55 caps, has been dogged by injuries in recent years and has made one international appearance as a replacement since 2017.
Russell, one game away from his half century of Scotland outings, told the BBC last month: “Everything’s better now with my relationship with Gregor.”
The Racing 92 number 10 was suspended for his breach of protocol and departure from the camp, while he later criticised Townsend in a newspaper interview.
However, the relationship between player and coach has been mended by a series of conversations since the Six Nations was brought to a premature halt by the coronavirus crisis.
Scrum-half Steele, 27, gets his chance after joining Harlequins from London Irish in July.
Prop Kebble, 28, has been with Glasgow Warriors since 2017, while fellow South African Van der Merwe, 25, has made an impressive impact on the wing for Edinburgh over the past three seasons.
Scotland warm up against Georgia at Murrayfield on 23 October before completing their delayed Six Nations campaign in Wales eight days later.
Townsend’s side then compete in the new Autumn Nations Cup in November with games away to Italy and at home to France and Fiji.
With a visit to Llanelli to come, Scotland sit third in the Six Nations table following wins over France and Italy.
“There was a strong feeling that we were growing as a team during the Six Nations earlier this year, making progress from game-to-game as well as building closer bonds within the squad,” said Townsend. “Our aim is to keep this momentum going.”
Forwards: Simon Berghan (Edinburgh), Jamie Bhatti (Edinburgh), Fraser Brown (Glasgow Warriors), Blair Cowan (London Irish), Scott Cummings (Glasgow Warriors), Cornell du Preez (Worcester Warriors), Matt Fagerson (Glasgow Warriors), Zander Fagerson (Glasgow Warriors), Grant Gilchrist (Edinburgh), Jonny Gray (Exeter Chiefs), Richie Gray (Glasgow Warriors), Rob Harley (Glasgow Warriors), Nick Haining (Edinburgh), Oli Kebble (Glasgow Warriors), Stuart McInally (Edinburgh), Willem Nel (Edinburgh), Jamie Ritchie (Edinburgh), Sam Skinner (Exeter Chiefs), Rory Sutherland (Edinburgh), Blade Thomson (Scarlets), Ben Toolis (Edinburgh), George Turner (Glasgow Warriors), Hamish Watson (Edinburgh).
Backs: Darcy Graham (Edinburgh), Nick Grigg (Glasgow Warriors), Chris Harris (Gloucester), Adam Hastings (Glasgow Warriors), Stuart Hogg (Exeter Chiefs), George Horne (Glasgow Warriors), Damien Hoyland (Edinburgh), Sam Johnson (Glasgow Warriors), Huw Jones (Glasgow Warriors), Blair Kinghorn (Edinburgh), James Lang (Harlequins), Sean Maitland (Saracens), Ali Price (Glasgow Warriors), Finn Russell (Racing 92), Scott Steele (Harlequins), Duhan van der Merwe (Edinburgh), Duncan Weir (Worcester Warriors).