Nugent's Preston move 'breaks down'
They gave him permission to talk to Championship side Preston, but talks appear to have broken down on Thursday over personal terms.
United launched a bid for the player on Wednesday, but have not disclosed the amount they were willing to pay.
He is said to favour a move to the Championship, and does not want to leave Gigg Lane for a League Two club.
Chester City made a bid of £65,000 plus further incentives last week, while Sheffield United and Crewe Alexandra are also chasing him.