Manchester United, Middlesbrough, Roma, Galatasaray and Valencia have all shown interest.
Leeds' caretaker boss Eddie Gray, who brought Viduka back after his bust-ups with previous manager Peter Reid, is sad his Leeds career is finishing on such a low note. "It's disappointing for him and it's disappointing for the club," said Gray, whose own future will be decided next week.
"I don't look upon him as a villain. He got a little over-zealous last week at Bolton. He knows that, but he's been a good football player for this club. I think the supporters will have fond memories of him. Those four goals against Liverpool were the highlight, as well as his performances in the Champions League."