Sassuolo has confirmed defender Francesco Acerbi has undergone successful surgery to remove a tumour.
Acerbi, 25, was found to have the presence of a abnormal growth in his urogenital system that required immediate surgery at a Milan hospital during a pre-season medical examination.
A statement published on Sassuolo's official website read: "The surgery was a complete success and the player is observing a period of convalescence after being discharged.
"A timeframe for a return to competitive action will be discussed over the coming days."
The statement did not specify if the removed tumour had been malignant or benign.
Acerbi joined newly-promoted Sassuolo from Genoa earlier this month and Italy international has also represented AC Milan and Chievo in the top flight.
Information from the Press Association was used in this report.