Kisnorbo, 30, had sustained an Achilles injury in March last year which kept him out of action throughout the 2010-11 campaign until he managed a brief appearance off the bench in Leeds' final game of the season.

The Australian, who won Leeds' 2009-10 Player of the Year award, returned to Leeds training on Monday after an off-season re-hab programme in Australia as he tries to fully overcome the Achilles problem which has ruined his past 15 months.

Kisnorbo, who missed selection for the 2010 World Cup due to the injury, is hoping to prove his fitness to Grayson in order to win a new deal with the club after his contract expired.

Grayson told the leedsunited.com he was delighted to have Kisnorbo back on the training paddock

"It's good to see Paddy working with the lads after doing his re-hab,” Grayson said.

“As I've said before, he's had a tough time, but he's looking to come through pre-season unscathed and get into the games with us now.”

Grayson has said Kisnorbo must prove he is over the Achilles injury to win a new deal with United, although he is hopeful that can happen.

“If Paddy is anywhere near back to where he was before his injury, it will be a massive boost for us – like signing a new player," Grayson told The Bradford Telegraph.

“We don’t want to put too much pressure on him because he only had 10 minutes’ Championship football at the end of last season and there is a bit of work still to be done in terms of games.

“If everything goes to plan and he doesn’t have any setbacks with other parts of his body, I can see him being involved in our whole pre-season and being back for the start of the season."

Kisnorbo was also linked with Crystal Palace over the weekend by Sky Sports UK.