The mastermind of Rob Ford's 2010 election victory has indicated that he will not work on the Toronto mayor's re-election campaign unless Mr. Ford enters rehabilitation for substance-abuse problems.

Sources with close relationships to both Nick Kouvalis and the Ford family told The Globe and Mail that Mr. Kouvalis, who was Mr. Ford's campaign manager and briefly his chief of staff, has cited concerns about Mr. Ford's health and his ability to withstand the pressure of another campaign.

The mayor's office has experienced an exodus amid allegations of a video purported to show Mr. Ford smoking crack cocaine. Mr. Ford has denied that he uses crack cocaine and said no such video exists.

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Six of his staff have quit and one has been fired – the latter being former chief of staff Mark Towhey. The Globe has reported that Mr. Towhey was let go after telling Mr. Ford he should seek addiction treatment. It has not been established that Mr. Ford has an addiction.

Mr. Kouvalis's distancing is a blow to Mr. Ford's re-election efforts, for which the mayor said this week he is already "getting things tuned up."

Mr. Kouvalis, who heads the firm Campaign Research alongside Ontario Progressive Conservative Party president Richard Ciano and recently worked on the British Columbia Liberals' come-from-behind re-election, has been credited with bringing discipline to Mr. Ford's 2010 campaign and for devising a winning strategy around opposition to city hall's "gravy train."

Although Mr. Kouvalis left the mayor's office in 2011, he has maintained a close relationship with Mr. Ford and remained an important political ally.

"I love the Ford family, and I will do everything I can to help them," Mr. Kouvalis said when asked to comment.

The mayor's office has declined to comment, and it is unclear if Mr. Kouvalis had been expected to run Mr. Ford's campaign.

Despite having been engulfed in controversy since reports of the alleged video emerged more than three weeks ago, Mr. Ford has been polling at more than 30-per-cent support – fuelling expectations that he will remain competitive.

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But the potential absence of Mr. Kouvalis and the departure of other long-time loyalists – the likes of Mr. Towhey, who was director of policy during Mr. Ford's 2010 campaign, and Kia Nejatian, who was director of field organization – raises questions about who would run the re-election efforts.

With a report from Sunny Dhillon