The 30-year-old, who scored 33 goals for Benfica last season, has been strongly linked with a move to Cardiff City in recent weeks.
"His transfer will certainly be finalised before July 17. He will not return to Benfica for pre-season," his representative Pedro Aldave told O Jogo.
"We are very advanced but I prefer not to go into more details."
A number of European clubs are also reported to be monitoring proceedings.