The Belgian underwent scans on Friday at the CFA.
No surgery is needed but he is expected to be out for between 5-6 weeks.
At Friday's press conference boss Pep Guardiola said: "Unfortunately he is injured but fortunately he will come back in four-six weeks," before adding: "He was so sad. But today less sad and tomorrow he will be stronger again. He can spend time with his family, then it's international break and then he will be back."
Stay tuned to mancity.com for further updates on his progress.