Sheffield United in three-way battle with Newcastle United and Crystal Palace for Championship star - report

The 22-year-old midfielder has caught the eye of several Premier League clubs this season and has been linked with a move away from the John Smith’s Stadium during the January transfer window.

Now The Football Insider is suggesting that the Blades have entered the race to sign O’Brien, along with Newcastle United and Crystal Palace.

It is understood the Terriers could be willing to cash in on O’Brien – regarded as one of the club’s star performers – this month for the right price.

He is out of contract in the summer of 2022, although his deal also has the option of an extra year, and had been linked with a move to the Blades’ Premier League rivals Burnley last summer.

O’Brien has started 16 Championships matches this season and is predominantly a central midfielder but can also operate in more advanced positions of the pitch.

The rumours linking United with a move for the Colchester-born star comes as the club is resigned to losing the services of John Lundstram, whose current contract expires this summer.

He is now free to sign a pre-contact agreement with a 'foreign' club – which includes any playing in Scotland – and has been linked with a move to Rangers.

"There's been no enquiries for John," Blades boss Chris Wilder admitted before this month’s transfer window opened.

"If someone comes in we have to assess that because they will have to come in with a fee and we will have to assess whether it's worth doing that or not."