Ling, who was sounded out by the Kangaroos for a full-time assistant coaching role earlier this year, as well as fielding interest from Melbourne, Richmond and Geelong, has increased his commitment to Channel 7, where he will replace Leigh Matthews in the Friday night special comments role next season.

Ling joined the Roos in a part-time role this year, working closely with the club's leadership group of captain Andrew Swallow, Jack Ziebell, Drew Petrie, Daniel Wells, Scott Thompson, Nick Dal Santo and Sam Gibson.

North Melbourne director of football Geoff Walsh said on Thursday that while the Roos were sorry to lose Ling, his media commitments would make the mentoring role too difficult to squeeze into his schedule.

"He came to a bit of a fork in the road at the end of the footy season with some coaching options on the go, but the media stuff particularly will be ramping up," Walsh said.

"I think he's decided he'll give that a good crack for a couple of years and see where he wants to go in a footy sense from there, but it's certainly going to squeeze him out time-wise."

Ling said he had enjoyed his time with the club and felt that the Roos' leaders had made genuine progress.

"It was a fantastic challenge and I did really enjoy it," he said. "But they're looking to expand it with a person who can take up a matchday role and unfortunately my schedule just doesn't allow it. Hopefully they can find someone who can really help take it to that next level."

Ling will work for Channel 7 on its Friday and Saturday night broadcasts in 2015 and is expected to continue his role with radio station 3AW. He is also heavily involved with several bars and restaurants in Geelong. "I think that's all going to keep me pretty busy," he said.

Walsh said the Roos were keen to replace Ling with another respected leader in football from outside Arden Street, though candidates wouldn't necessarily be restricted to recently retired players.

"You're going to get a much better effect if you've got someone who's driving them and pushing them in a certain direction, and in all those areas you want to see in your leaders, so I think you need someone - and generally that's an external person - who can come in and do that.

Walsh said North Melbourne hoped to have a replacement for Ling in place before the players returned from their break for pre-season training.

"We've got a number of things in terms of appointments and re-contracting of staff to sort out, so that's in the mix," he said.

"It's all on the table to be completed, hopefully sooner than later, but there's no specific timeline on it other than we want to have all those sorts of things in place before the players come back for training."