FIANNA Fail's "prim aunt" could become kingmaker in the leadership battle if she agrees to accept a deputy position.
Mary Hanafin has little or no chance of taking the top job but sources say that she may privately persuade her supporters to pass second preferences to one of the frontrunners.
The move could see her be offered a position as deputy leader of the party and substantially increase her chances of re-election in Dun Laoghaire.
The calculated move could be the difference between Micheal Martin and Brian Lenihan in the vote that is being operated under the PR-STV system of transfers.
"It seems clear that Hanafin knows she can't win but there are other games at play," said a source.
Ms Hanafin will have to engage in a dog-fight to retain her seat in an area dubbed the "constituency of death".
She has raised her public profile significantly in recent weeks by voting against Taoiseach Brian Cowen in the confidence vote which he won.
But significantly her running mate and fellow Cabinet member Barry Andrews has given his backing to Micheal Martin.
Analysts say that only one of the two ministers will win a seat but they may even cancel each other out and allow other parties to take advantage.
Asked about her leadership ambitions yesterday, Ms Hanafin said: "Politics is my life. Fianna Fail is my life. I devote all of my time and energy to it. I don't have anything else."
Micheal Martin remains the firm favourite to win tomorrow's vote, although Brian Lenihan is thought to have "a respectable" level of support.
Dublin-born Eamon O Cuiv is seen as a rank outsider along with Ms Hanafin.
Unusually supporters of outgoing leader Brian Cowen have not diverged towards a single candidate but are scattered between all four.
All four contenders were working the phones yesterday as they tried to make contact with each individual TD in an attempt to drum up support.
This was proving especially difficult for Mr Lenihan as his role as Finance Minister meant his time was severely limited by meetings.
However, Mr Lenihan says that he is not overly concerned by the head-start afforded to his main rival.
"I am encourage by the considerable numbers in my parliamentary party who have privately committed their support, and I look forward to the opportunity of making my case for the leadership at the parliamentary party meeting," he said.
In a statement issued last night, he added: "The crucial issue for our party and indeed, for the country is that we remain a substantial and cohesive political force in Irish life.
"The new leader must be a straight talking, decisive moderniser in the Lemass mould, with a strong sense of the State and the common good."