Griezmann makes the revelation in his new book, 'Behind a smile, the life of the Little Prince told by himself'.
"While I have everything to be happy, this doesn't mean I won't leave one day," he writes.
"I have not made a decision. It all depends on several factors.
"As much as I repeat that I am delighted at Atletico, I have a great coach and great teammates, they regularly ask me about my future.
"I don't exclude anything, I have nothing against England, apart from the weather and Manchester United is a possibility."