The 25-year-old's form in a season where he was voted the supporters' club Player of the Year has made the defender a top target for both Wigan Athletic and Burnley.

New Latics manager Roberto Martinez is believed to be a huge fan of Kilgallon after being impressed by his displays for United in their two games against the Spaniard's then club Swansea City last term.

Burnley, who denied the South Yorkshire club promotion in last month's Championship play-off final at Wembley, are also tracking the £1.75m signing from Leeds United as they prepare to embark on their first foray into the top flight since 1976.

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The interest comes at a time when the Yorkshire Post understands talks over a contract extension for Kilgallon have stalled with the player wanting better terms than the club are willing to offer.

A block was put on all talks over possible new deals at Bramall Lane last January until it was known whether United would kick off the 2009-10 season in the Premier League or Championship.

The subsequent failure to win promotion means the £11m parachute payments for clubs relegated from the top division will end this summer, drastically reducing the Blades' spending power.

York-born Kilgallon was signed by then manager Neil Warnock in January, 2007 but he had to wait for his debut due to an ankle injury picked up in his last game for Leeds. It meant he managed just six appearances as United slid out of the top flight in heart-breaking circumstances.

Since then, however, he has continued to mature as a player and last season his partnership with Chris Morgan at the heart of the defence was a major factor in the Blades coming within a whisker of winning promotion.

No bids have been made yet but if Wigan or Burnley want to be successful in their quest for the highly-rated defender then it is likely to take a substantial offer to prise him away from Bramall Lane.

Wigan manager Martinez has already recruited Jordi Gomez, the Espanyol midfielder who spent last season on loan at his former club Swansea, and is keen on his former striker Jason Scotland.

On other possible targets on his Spanish manager's wishlist, Latics chairman Dave Whelan said yesterday: "There are a lot of players away on holiday and I think the market will only rev up in about a week or 10 days."

Speculation also continues to surround the futures of Blades defender Kyle Naughton with Everton and Aston Villa both understood to be keen.

Clearly, many of United's players are in demand with Middlesbrough also believed to be interested in Nick Montgomery but manager Kevin Blackwell has remained focused on his own summer recruitment drive.

Watford midfielder Lee Williamson has already been signed by the Blades chief and is expected to be followed through the door by West Ham United winger Kyel Reid following the successful completion of a medical.

Blackwell is, it seems, keen to bring players with bags of potential to Bramall Lane as the club look to make it third time lucky in their attempt to get out of the Championship and back to the top-flight.

Manchester City's Ched Evans is another highly-promising player wanted by the Blades chief, who is now hoping that Roque Santa Cruz's switch to Eastlands will pave the way for Mark Hughes to accept a reported £1.5m bid for the striker.

Talks are also believed to be on-going over a number of United's other targets as Blackwell looks to build a side capable of going one better than last season.

Meanwhile, United have announced that the age for fans able to take advantage of concessionary prices at Bramall Lane has been raised from 16 to 18-years-old.

The club have also increased the number of Category B fixtures, whereby fans can get in cheaper, compared to last season while also maintaining the popular £10 and £5 category C priced matches for a minimum of four games.

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