The Sun says the Barcelona midfield dynamo, 26, is reportedly becoming worried as he is still waiting for assurances about his Nou Camp future.
And he has told friends he would welcome a move to Old Trafford if his prospects do not improve under new Barca boss Gerardo Martino.
United have already made two approaches for Fabregas after making an initial £26million offer and a club-record £31m bid.
Both were rejected but United boss David Moyes, who has made no secret of his desire to land the former Arsenal ace, said yesterday the move to sign him was ‘ongoing’.
United are determined to continue their pursuit — especially as they are aware Fabregas is open to the switch — and will go as far as £35m.