JOHN Barker's coaching mentor, the former Australian cricket coach John Buchanan, warned the Carlton candidate of the dangers of taking on an interim role with the club back in May.

Two weeks before Mick Malthouse was sacked and Barker was confirmed as the caretaker coach for the rest of the season, Buchanan and Barker caught up as part of the AFL's Level Four Senior Coach program.

Buchanan, who has worked with Barker this season in his career development, mentioned the brand damage that can be done to an aspiring coach when he takes on such a role. 

He also advised the 40-year-old, who has a 2-8 record while in charge of the Blues, that he would have little scope to change the way Carlton is playing and operating away from game day this season.

"John was keen to have a run at it and my conversation with him was around being well aware of both the pros and the cons of what it can do for your career," Buchanan told  

"As an interim coach there are only a few things you can possibly do, so you can't go about clearly demonstrating everything you can do and everything you can bring.

"All you can do is maybe fine tune and polish up a few key things, and even if that translated into results, it's still difficult for people to see you as a head coach.

"The upside obviously is it puts you in the running and people see you in a different light."

Buchanan said Barker had no doubt he wanted to step into the role and it was the right thing for him to do at the time. 

The former Hawthorn forward was interviewed by the Carlton sub-committee at length on Thursday, but he has slipped out of favouritism in the race for the senior position.

Buchanan said the Blues sub-committee would have gained an insight into Barker's credentials by the way he moved from the assistant role to the senior position, but they should look at the whole picture.

"It'll be about what the Blues have demonstrated on the field that wasn't evident when Mick Malthouse was there, but I think in terms of his time there that's all they can assess," he said. 

"There would be certain things that should have been seen – either on-field or off-field – that should benefit John.

"Ultimately the selection panel has got to consider everything else he can bring." 

Buchanan also mentors Port Adelaide assistant Matthew Nicks as part of the coaching accreditation course, which also includes Brendon Bolton (Hawthorn), Stuart Dew (Sydney Swans), Simon Lloyd (Fremantle), Blake Caracella (Geelong), Robert Harvey (Collingwood), Adam Kingsley (St Kilda) and Simon Goodwin (Melbourne).

The 62-year-old, who led Australia during one of its most dominant cricketing eras, is viewed by most of his former players as an intense thinker and a man of ideas, prompting the AFL to seek his services.

A corporate leadership advisor and coach, he was a fan of the Level Four program, which could become mandatory for all aspiring senior coaches.

"Over time former players can be exposed to this sort of program, which I think would have huge benefits given it's very difficult moving out of playing and straight into senior coaching," he said.   

"In recent times we've seen some interesting examples."