Bigon left Naples for Germany, but spent time on a stopover in Belgium, which has sparked rumours of a meeting with Manchester United midfielder Marouane Fellaini.
Fellaini has been given extra time off after his World Cup campaign with the Red Devils, but has also been linked with a move away.
Napoli are keen, but United will have to accept a major hit on the £27 million they paid Everton for Fellaini just 12 months ago.
Azzurri coach Rafa Benitez has made it no secret he wants find a new midfield signing this summer.