City confirmed the injury on their official website, with the player leaving the pitch at Wembley Stadium in the first half. Sane will have surgery before he starts his rehabilitation.
A statement from City read:
"He has undergone testing throughout the week, with a specialist doctor travelling to Manchester for further examinations to understand the extent of the injury. Leroy will have surgery in the coming week. Manchester City will provide Leroy with all the support and guidance he needs, and everyone connected with the club wishes him a quick and full recovery."
Pep Guardiola had said he did not believe the injury was serious immediately after the game, according to Simon Mullock of the Mirror. The 23-year-old twisted his knee in the opening moments and could not continue. City went on to win the Shield with a 5-4 victory on penalties after a 1-1 draw in normal time.
Both Kicker and Bild (h/t Goal's Ronan Murphy) reported the player could be set for a move to Bayern Munich. However, any deal will now surely have to wait until Sane returns to action.