The former striker joined the academy from Dublin side Belvedere and was quickly elevated to the reserve side.

He made 14 senior appearances for Celtic but failed to make a lasting impact.

Sheridan, who went on to play for St Johnstone, Kilmarnock, and Dundee, now feels that his mentality and self-belief were not strong enough.

He told the Scottish Sun: "When I look back at all the ones who came through at Celtic and made it—it was a mentality thing.

"It was the players who got a chance in the first team and believed they should be there.

"They would say, 'This is my chance... I'm a first-team player and I am better than the guy I'm coming in for.'"

Sheridan admitted he did not have the same mindset.

He added: "Personally, I would view it as 'I am only in because someone is injured.' I would be waiting to be replaced.

"I find that’s the difference between players who go to the top level.

"Those who break in at any of the big clubs and stay for the long term, always have the mentality."

Sheridan was speaking as he promoted his first 'In Good Company' event, which will see former players like Aiden McGeady and James McFadden as speakers.

Both McGeady and McFadden, according to Sheridan, had the mentality needed to succeed at big clubs.

"There are players, like Aiden and Faddy, who have ridiculous talent, but they also had the belief," he said.

"It’s one thing being a teenage prodigy, but if you don’t have the mindset to go with the talent then you won’t make the most of your career."

Sheridan recalled a conversation with McGeady when he had six months left on his contract.

He said: "I said something like, 'I’m really going to step it up so that I can get a good move' and his reaction was, 'Why are you not always like that?'

"It’s true. You shouldn’t be switching it on and off.

"Aiden had so much talent but he also put the extra work in that people didn’t see."