Boro made contact with Viduka following Leeds' relegation from the Premier League.
However, it is believed the Teessiders have been warned off making a bid for Alan Smith after being told he is not interested in a move to The Riverside.
Viduka was labelled a "Vidiot", "stupid", "disgraceful", "petulant" and a "villain" by the press after he was sent off in the 4-1 defeat at Bolton on Sunday.
Viduka's agent Andrea d'Amico said he would be in a position to discuss the Aussie's future next week. "There's too much confusion now. At the moment, there is nothing serious," d'Amico said.