Napoli are interested in Suso if he fails to agree a new contract with Milan, claims Spanish paper Marca.
The winger joined from Liverpool for just €1.3m in January 2015 and truly made an impact after a loan spell at Genoa.
This season he has contributed seven goals and 11 assists in 35 competitive games for Milan.
Suso has so far struggled to agree terms on a new contract, as his current deal is due to expire in June 2019.
According to Marca, Napoli have set their sights on the 23-year-old Spain international, who would be an alternative to Jose Callejon.