Inter have confirmed Romelu Lukaku will be absent for at least a week with a thigh injury.
The Belgian forward sustained the issue in a training session on Sunday and will be reassessed next week, though his absence means he will miss two crucial games for the Nerazzurri.
Lukaku will be forced to watch on in Tuesday's Serie A clash against Cremonese and will remain absent for the derby against defending champions Milan this weekend.
It is also likely that the Chelsea loanee will not be able to feature when Inter commence their Champions League campaign against Bayern Munich next week.
A statement on Inter's website confirmed Lukaku had suffered an injury to the flexor of his left thigh and said his condition will be re-evaluated next week.
Reports in Italy have suggested Lukaku could be out for a longer period of 20 days, which would mean missing further clashes against Torino and Udinese in Serie A and Viktoria Plzen in the Champions League.
Inter have picked up six points from their opening three league matches, beating Lecce and Spezia before defeat to Lazio on Friday.