Sky Sports understands a host of Football League clubs are tracking non-league hot-shot Scott Fenwick.
Middlesbrough boss Aitor Karanka has revealed that the club have opened contract talks with captain Grant Leadbitter.
Both Wolverhampton Wanderers and Nottingham Forest have also been linked with the 21-year, who has already played 130 games for the Blades, but Sky Sports sources understand Hull head the list of potential suitors.
Maguire told Sky Sports News earlier this month: "Playing in the Premier League and Europe will be a dream for me at this stage of my career.
"I've played nearly 170 games, I'm just 21 and the Sheffield United fans know I've given my all in every game I've played."