The player's brother and representative has played down talk of a move to the Turkish giants as he reacts to widespread speculation regarding the Flamengo star
Reports in Turkey have surfaced regarding a supposed interest from the Istanbul-based side.
Talk has centred around a move in the summer of 2012, whereby the former Barcelona and AC Milan man will be offered a top pay deal.
However, De Assis has moved quickly to respond and said he did not know of any concrete interest from the Super Lig outfit.
"I am surprised [at the Galatasaray rumours] for the moment," De Assis is quoted as saying on Tuttomercatoweb.com.
"I am unware of these voices."
Ronaldinho has been in stellar form for his club, scoring 13 goals in 22 starts in the Brazilian Serie A this season.
He has also won back the faith of Brazil coach Mano Menezes following his recent return to the national side.