Manchester City forward will undergo a knee surgery in the coming days after damaging his cruciate ligament in the Community Shield victory over Liverpool.
Sane suffered an injury to his right knee just 13 minutes into the match at Wembley.
The winger has been linked with a transfer to Bayern Munich this summer but the injury means the chances of making the move are very low.
City released a statement on their website with kind words for the midfielder. It read:
“He [Sane] has undergone testing throughout the week, with a specialist doctor travelling to Manchester for further examinations to understand the extent of the injury.
“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.”
The champions commence their title defence at West Ham on Saturday, kick off 12:30 BST.