Chelsea teammate Tammy Abraham, who made his senior debut for England against Germany in 2017, could also be included after scoring two in Chelsea’s 3-2 defeat of Norwich on Saturday.
Southgate is a fan of Mount, having invited him to train with the seniors before last year’s World Cup.
The 20-year-old, who has scored two goals in four games so far this season, was called up for the Nations League matches last year but is yet to earn a cap.
James Maddison will be sweating over his inclusion in the squad after Southgate was reportedly unimpressed with his showing at the Under-21 Euros this summer.
Aaron Wan-Bissaka is also expected to join the senior side, but faces stiff competition for the right-back position from Kyle Walker and Trent Alexander-Arnold.
Goalkeeper Jack Butland’s poor early season form could pave the way for uncapped Man Utd keeper Dean Henderson, on loan at Sheff Utd, to be included.