Maple Leafs general manager Cliff Fletcher told The Canadian Press on Friday that the team had given its permission, but he had no other comment.
"We have given Montreal the exclusive rights to talk to him up until 12 noon on July 1 when he becomes a free agent," Fletcher said. "It's not in my best interest to say anything else, it's not in Montreal's best interest and not in Mats' best interest."
Sundin has been with the Maple Leafs since being acquired in a trade from the then-Quebec Nordiques at the 1994 draft. He is the franchise leader in points and goals.
"At this point Mats still hasn't decided if he wants to play, let alone where," said Sundin's agent, J.P. Barry. "But obviously the Leafs are trying to facilitate a decision."