Werder Bremen have revealed that Italian giants Juventus are keen on signing Diego this summer.
The Brazilian playmaker has been a target for the Serie A outfit for some time, while the likes of Chelsea have also been heavily linked with him in the past.
He has remained loyal to the Bremen cause until now, but could find himself taking on a new challenge at the end of the season.
His current employers remain reluctant to part company with their prized asset, but have admitted to holding discussions regarding Diego's future.
"Of course there have been talks," Bremen's general manager Klaus Allofs told Kreiszeitung.
"If there is a club expressing an interest in one of your players it is usual for you to give them a call.
"But we have not entered into transfer negotiations with Juventus."
Allofs added: "We remain determined to keep Diego here until at least the end of his contract (in 2011), while we are still trying to persuade him to sign an extension."
Meanwhile, Juventus are set to appeal the Italian football federation's decision to force them to play Sunday's home game with Lecce behind closed doors.
The sanction was imposed after a section of Juve fans were deemed to have directed racist abuse towards Inter Milan striker Mario Balotelli during a recent contest at Stadio Olimpico.
The Bianconeri saw an initial appeal rejected on Tuesday but are already preparing another as they feel the reasons behind the punishment have not been fully explained.