Ronaldinho's agent insists he is not looking to move the Brazilian playmaker out of Barcelona.
But De Assis has played down recent visits to England and Italy, after Milan also declared an interest, and says he is not trying to negotiate his brother's summer exit from Barcelona.
"My work is connected with the world of football and it is usual for me to travel and talk about personal matters when I think it is necessary," De Assis told Don Balon.
"Ronaldinho has a contract until 2010 and I am not looking for anything."
The former Paris Saint Germain star has been ruled out for the next six weeks through injury, but de Assis also quelled suggestions Ronaldinho has played his last game for Barca.
He said: "It's a little early to say that.
"I hope he can be playing again soon. I think a player who has been in the hearts of Barca fans and this group of players deserves to leave on a high.
"Decisions need to be taken calmly at the right time, not in the heat of the moment or in difficult times."