The 26-year-old Thompstone has scored 12 tries in 37 appearances for Tigers since moving to Welford Road from London Irish in the summer of 2012.
Voted Newcomer of the Year in the supporters’ awards last season after finishing his first year with the club as top try-scorer, Thompstone is making his first appearance in a squad at Saxons level.
He is among three players added to the Saxons squad for the game against Scotland A in Glasgow on Friday (7.30pm).
Gloucester scrum-half Dan Robson and Newcastle’s former Tigers prop Kieran Brookes have also joined the squad training at Loughborough University.
Bath wing Semesa Rokoduguni – ruled out of last week's 14-8 defeat against the O2 Ireland Wolfhounds – has returned to training ahead of Friday night's game at Scotstoun.
Those making way are Northampton prop Tom Mercey (knee), Exeter centre Sam Hill (hamstring) and Harlequins centre Matt Hopper (rib).
Robson takes over from Dave Lewis (Exeter Chiefs) while Anthony Watson (Bath) has rejoined the England senior squad. A further addition to the backs available to Head Coach Jon Callard will be made in due course.
Kieran Brookes (Newcastle Falcons)
Nathan Catt (Bath Rugby)
Calum Clark (Northampton Saints)
Sam Dickinson (Northampton Saints)
Dave Ewers (Exeter Chiefs)
Jamie George (Saracens)
George Kruis (Saracens)
Charlie Matthews (Harlequins)
Elliott Stooke (Gloucester Rugby)
Luke Wallace (Harlequins)
Alex Waller (Northampton Saints)
Dave Ward (Harlequins)
Scott Wilson (Newcastle Falcons)
Freddie Burns (Gloucester Rugby)
Elliot Daly (London Wasps)
Rob Miller (Sale Sharks)
Dan Robson (Gloucester Rugby)
Semesa Rokoduguni (Bath Rugby)
Charlie Sharples (Gloucester Rugby)
Joe Simpson (London Wasps)
Henry Slade (Exeter Chiefs)
Adam Thompstone (Leicester Tigers)