Lorenzo Insigne's agent has revealed that Sunderland enquired about the Napoli forward earlier this summer.
Insigne broke into Napoli's first team in a strike partnership with Edinson Cavani last season, scoring five times in 37 appearances.
The 22-year-old's agent Fabio Andreotti admitted that his client rejected Paolo Di Canio's interest in a loan deal last month, while declaring that he wants Napoli to open talks over a new contract.
He told Radio CRC: "The Sunderland rumour is true. But Lorenzo wants to stay here, even if it means earning less money.
"His renewal? We just want justice, Napoli still haven't contacted us, we are waiting for them.
"We have clear ideas and he wants to stay. However, there have been clubs with enough courage to ask Napoli about his asking price."
Insigne's current contract at the San Paolo Stadium expires in 2017, but after a strong showing for Italy at the recent European Under-21 Championships the forward wants improved terms.
Liam Power
