World Cup winner Gennaro Gattuso is under investigation for match-fixing.
Police have arrested four others in connection with the case which is believed to have involved more than 30 matches stretching back to 2009.
Gattuso’s agent has been quoted as saying his lawyer is in contact with the prosecutor about the matter.
Italian Gattuso, 35, twice won the Champions League with Milan. He was sacked as manager by Serie B Palermo in September after a string of bad results.
Former Lazio, AC Milan and Inter Milan player Cristian Brocchi is also being investigated.
The investigation was triggered by a second-tier Serie B match in Cremona in 2010 which aroused suspicions that led to a wider probe.