"Eventually it was the politics at Leeds and obviously, the deal is complicated,'' said McClaren. "It's not just a straight one with Leeds United.
"I think there are other parties involved in the deal, and coming to an agreement with them in the short time that we had was just an impossibility.
"He would have been a tremendous addition to this football club, but it wasn't to be and we move on.''
"Mark is very serious and he was waiting for a good option," Viduka's agent Andrea D'Amico said.
"At this moment, it's OK to stay at Leeds because he wants to help the team and he's important for Leeds to stay in the Premiership.
"But Mark at this moment doesn't want to comment, the only thing he wants is to play and do the best for his team."
"I think there are other parties involved in the deal, and coming to an agreement with them in the short time that we had was just an impossibility.
"He would have been a tremendous addition to this football club, but it wasn't to be and we move on.''
"Mark is very serious and he was waiting for a good option," Viduka's agent Andrea D'Amico said.
"At this moment, it's OK to stay at Leeds because he wants to help the team and he's important for Leeds to stay in the Premiership.
"But Mark at this moment doesn't want to comment, the only thing he wants is to play and do the best for his team."