Investigators said the involvement of Suljic, 31, a Slovenian citizen, has been noted in a series of probes into betting-related fixing of soccer matches in Italy in recent years.
Over 40 people have been arrested since the first of the investigations, called "the Last Bet" criminal investigation in Cremona, Italy, was publicized in 2011, the Italian news agency ANSA reported Thursday.
The arrests have included soccer players Stefano Mauri, Beppe Signori and Cristiano Doni.
The European police agency Europol said earlier this month it identified 680 suspicious soccer matches, including European Champions League matches.
Suljic, who was arrested after arriving in Milan from Singapore, is an alleged associate of Tan Seet Eng, a Singapore national and alleged kingpin of soccer match-fixing, ANSA said.