Blatter has come in for criticism lately for his leadership of world football's governing body, with FIFA coming under increasing scrutiny regarding corruption allegations.
The accusations concern the decision to award the 2022 FIFA World Cup to Qatar, with high-ranking officials in the game voicing their wish for Blatter not to stand for re-election in a meeting on Tuesday.
Despite the calls for him not to do so, Blatter announced his decision to stand on Wednesday, thus going back on comments made in 2011 which indicated he would step down at the end of his current term.
Platini, touted as a leading candidate to run in opposition to Blatter, revealed on Thursday that the Swiss had lost his backing.
"I am supporting him no longer, it's finished," the Frenchman told L'Equipe.
"I have known him for a long time, I like him, but I'm not favourable to him having another term.
"I supported him in 1998, but I do not support in 2014. And in the future, I shall not support Blatter. I told him that. I think FIFA needs a breath of fresh air."
When asked if he could oppose Blatter, Platini explained: "It is an option.
"But it is not because of Blatter that Michel Platini would stand. And it is not because of Sepp Blatter that Michel Platini would not appear.
"My only concern is what I want to do. I am almost 60 years old and I need to know what I want.
"I just want to be sure what I want to do. In my life, I wanted to be a footballer, it went well.
"I was asked to coach, and to be president of the organising committee of the 1998 World Cup, I liked it.
"Then I became a member of the (FIFA) Executive Committee. Now I am very happy to be at UEFA. I am loved by national associations. But FIFA is something important."
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