Sheehan was left out of United's starting line-up at Wembley in May following his dismissal at Yeovil two weeks before the start of the play-off semi-finals, and the omission proved a painful experience for the 21-year-old defender.

The three-match suspension incurred by his two-footed tackle on Yeovil's Lee Peltier – a challenge described as "horrible" by Leeds manager Gary McAllister – had been served by the time United lined up against Doncaster Rovers in London on May 25, but Sheehan remained on the sidelines as an unused substitute after losing his place at left-back to Bradley Johnson.

His form prior to his ban had been impressive, however, and it was unsurprising to see McAllister convert his loan from Leicester City into a permanent deal by signing Sheehan on a three-year contract at the start of this month.

Sheehan is one of three players – along with Johnson and Ben Parker – who are possible candidates to occupy the left side of defence for Leeds next season, and the Republic of Ireland Under-21 international took a step towards holding that role against Scunthorpe United on August 9 by featuring in a strong starting line-up during Wednesday night's pre-season friendly against Galway United.

Sheehan said: "The red card was very disappointing and I haven't forgotten about that. I missed the play-offs because of it and I felt like I let down a lot of people, including myself.

"I'd come into form after a bit of a poor start at the beginning of my loan, and I was starting to repay the manager for giving me another chance at a pretty vital stage of the season. It was a stupid tackle and I paid the price.

"That's one of the reasons why I'm glad to be here for a second time. I feel like I've got to repay people again and earn my place in the team like I did last season. I'm only a young lad and I've got a lot of learning to do, but I think I'm in the best place to do that."

Leicester attempted to retain Sheehan by offering him a new contract at the end of last season but United secured his signature by striking a deal over compensation with the Midlands club, aided by the player's desire to move to Elland Road permanently.

Sheehan said: "I was really happy here last season and I found it easy to settle, especially when my form improved. Even after Leicester offered me a contract, my plan was always to come back to Leeds. It was the only place I wanted to be.

"No disrespect to Leicester because I've nothing bad to say about them, but I feel like I've moved to a different class of club."

Sheehan helped United secure a 2-0 win over Galway on Wednesday – the club's first victory of the summer – and the defender strode comfortably through 73 minutes, his longest outing since his appearance in United's League One clash at Millwall on April 19.

"To get through the best part 90 minutes is a nice feeling," he said. "I wasn't too short of energy at the end.

"As a squad, we're all in pretty good condition and we've still got a lot training to do and friendlies to come before the start of the season.

"We all realised that we'd have to come back in excellent shape because in every position there are at least a couple of lads trying to make sure they'll be in the starting team next season. You don't want to cause yourself a problem by beginning pre-season overweight or out of shape."