Sportsmail understands the Bundesliga champions have been left shocked by City’s £135million valuation of Sane, who has turned down the offer a new contract at the Etihad Stadium.
Sane’s situation is further complicated by a knee injury sustained during Sunday’s Community Shield that is believed to be worse than first anticipated.
The 23-year-old left Wembley with heavy strapping on his right knee after a clash with Liverpool’s Trent Alexander-Arnold.
There was hope earlier in the week that the problem was not serious but sources on Wednesday night described it as a ‘bad injury’.
It throws Sane’s immediate future into doubt, with the two clubs remaining some way a part in their valuation of the player following discussions.
Thursday's transfer deadline is not prohibitive given German clubs can still make signings until September 2 and the Premier League champions would not rush into landing a replacement.
City maintain they want market value for the 23-year-old and sources have pointed towards the fee Barcelona paid Dortmund for Ousmane Dembele in 2017.
