The Spain international, who played the first half of City's friendly victory over Hearts on Friday, has broken the fifth metatarsal in his right foot.
"I want to let you know that its going to be hard for the next few months, I fractured my 5th metatarsal and will be out a few months," Negredo wrote on his Instagram account with an accompanying picture of him wearing a protective boot.
"I will be back stronger than ever
I will return with a vengeance."
Source: PA