Trotters chief Phil Gartside made a move to bring Rodrigo back to the Reebok Stadium after the Benfica striker made a lasting impression while on loan in the 2010/11 season.
But his Portuguese employers are unprepared to let the highly-rated youngster leave and have told Bolton that the Spain Under-21 international is not for sale at any price.
Gartside confirmed to O Jogo: "I have tried everything to push through a deal for Rodrigo but the president of Benfica says he is not for sale at any price.
"President (Luis Filipe) Vieira says it not a question of money and that his decision is based on sporting factors.
"Benfica do not want to part with this player because they have high hopes for him.
"If Rodrigo had been with us this season, I am convinced that our situation would be different. Bolton need his goals but it is not possible.
"I am convinced that, in a few years' time, Rodrigo will be a global star."