Diogo has attracted enormous interest of late, having earned recognition as one of Brazil’s hottest prospects since helping Portuguesa to the top-flight last season.
The Sao Paulo native joined the senior squad in 2005 and has scored 22 goals in 29 games for his hometown team, alerting some of the world’s most prestigious clubs in the process.
The 21-year-old told Goal.com recently that he is ready to fulfil his dream of
playing on the biggest stage, while Portuguesa president Manuel da Lupa
insisted he would cost over €20million.
Arsenal have been linked with a move, as manager Arsene Wenger is desperate to add some firepower given the injury problems of Eduardo da Silva and Robin van Persie and the fact Emmanuel Adebayor could be leaving for AC Milan.
And club director Andre Heleno confirmed that the Gunners – among others – have already had a formal approach rebuffed.
"We have already refused an offer from Arsenal because it was too low," Heleno told Correio Manha.
"Until now, the biggest offer made to us came from Italy, with £9 million. We will only start to think of selling him from £12 million.
"Benfica have approached him via representatives that intend to bring him to Portugal, but there has not been any proposition yet.
"We have previously been contacted by Sporting but an offer was not made."