The Milan club released an official medical update following comprehensive scans in Rozzano to determine the severity of the setback.
In a statement published on Tuesday, Inter said: "Hakan Calhanoglu underwent medical examinations this morning at the Istituto Clinico Humanitas in Rozzano. The tests revealed an adductor muscle strain in his right thigh. His condition will be evaluated in the coming days."
Widespread reports across Italy confirm the muscle strain will keep him out of Saturday's crunch trip to the capital.