Police were called to a nightclub by a photographer late on Saturday after he was assaulted by AC Milan striker Mario Balotelli following an argument, according to reports.
Balotelli was ruled out of his side's away match at Sampdoria on Sunday due to injury.
Domestic news agency ANSA said Balotelli travelled to Liguria, on Italy's north-west coast, to watch a football match on Saturday in which his brother Enoch Barwuah was playing.
Balotelli later reportedly refused a photographer's request for a photo when he showed up at a restaurant with his fiancee Fanny Neguesha and some friends.
The party moved on to a nightclub, where the same photographer was waiting.
According to witness testimony, after refusing another request Balotelli and the photographer argued before the latter was kicked by the Italy international.
The photographer called police and later accompanied them into the nightclub to identify the 23-year-old player.