The Chelsea loanee underwent tests and it has now been confirmed that he picked up a second-degree calf injury.
Although the international break lasts until the following weekend, the 27-year-old could miss as many as seven games, including two Europa League fixtures and a clash with Champions League qualifiers Atalanta.
He joined the Giallorossi from Chelsea on an initial six-month loan in August, with the option to extend for the rest of the season.