The agent of Marek Hamsik admits the midfielder is eyeing a move away from Napoli. AC Milan and Inter Milan were blocked by Napoli president Aurelio de Laurentiis from buying Hamsik in the summer.
Manchester City and Manchester United are also watching the Slovakia international.
"I don't know if this will be Hamsik's last year at Napoli, but it is certainly a prison for him, albeit a golden one," declared controversial agent Mino Raiola on Radio Radio.
"I do not like players being held in a club against their will. I'm not just talking about Hamsik, but also Zlatan Ibrahimovic when he was at Barcelona."