The 21-year-old full-back became McAllister's second summer recruit yesterday, following on from the signing of former Swansea midfielder Andy Robinson.

The ex-Leicester man, pictured, impressed the Scot with his workaholic attitude during his loan stint at United in the second half of last season, although he fully expects Ben Parker to push him all the way in the battle for the left-back berth next term.

Sheehan was out of contract at the Walkers Stadium, but the Foxes are entitled to compensation with the player being under 24.

The two clubs are currently discussing a fee, but a tribunal will sort out the issue if they are unable to agree on a figure.

McAllister said: "I'm pleased. When we first brought him in, he struggled a little bit, but he was the first to admit that.

"The jump from reserve team to the first team may have been a bit too much, but he worked very hard, came back and did ever so well.

"One of the things that struck me was how hard he was prepared to work.

He was determined to win a contract here and I was impressed with his attitude.We know Alan is going to be here and with Ben Parker back with us (from a loan spell at Darlington), hopefully he will be pushing him on the left."

Sheehan made 10 appearances for United after joining in January, and memorably scored with a stunning free-kick in the 1-0 win at promotion rivals Doncaster on April 1.

The Galway-born defender joined Leicester in 2003 after being spotted playing for Belvedere FC and made his debut on the final day of the 2004/05 campaign.

He was Leicester's Academy player of the season in 2005, but was handed few first-team opportunities, spending a loan spell at Mansfield in 2006.

Sheehan fought his way back into the first-team reckoning at the start of last term, but fell out of favour under Ian Holloway.