When Celtic took Shane Duffy on loan from Brighton is September, his former youth coach at Everton believed the move was as close as you could get to a guaranteed success.

Former Celtic defender Alan Stubbs had helped take him through the ranks at Goodison and regarded the switch as a no-brainer for both parties.

Neil Lennon’s side had a soft centre in their rearguard and Stubbs was convinced that the rugged Republic of Ireland captain would fill that void. For Duffy’s part, Celtic offered him the opportunity of regular first-team games plus European football, neither of which were on offer at the Falmer Stadium.

Alan Stubbs explains why Shane Duffy has flopped for Celtic

Indeed, Duffy claimed on arrival that he hoped to do well enough to warrant the offer of a permanent move to his boyhood heroes so that he could experience playing in front of a full house but a campaign pock-marked by indecision, bad choices and an apparent lack of spatial awareness means that will not happen “I’d be very surprised if he gets that chance,” said Stubbs.“There are going to be wholesale changes and that’s started with Peter Lawwell and Neil Lennon leaving.

“With Shane, though, I think there’s an element of caring too much and trying too hard, which worked against him.

“All of his family are Celtic diehards as well but the biggest pressure comes from within. Shane would have desperately wanted this to be a success.

“He’d have wanted to play really well and for the season to have ended so much better than it has done. But it hasn’t and I don’t believe the instability of changing from week to week – from a back three to a four or a five – has helped him.

Alan Stubbs explains why Shane Duffy has flopped for Celtic

“Shane would have been at his best in a five. If you’d played Christopher Jullien and Kristoffer Ajer on either side of him you’d have a decent three plus a couple of wing-backs but injuries also prevented that from happening.

“Unfortunately, Jullien has been injury-prone ever since he joined and now he’s potentially out until Christmas.

“Ajer looks as though he might leave in the summer and it wouldn’t surprise me if Celtic had a completely new back four next season.

“They also definitely need a new ‘keeper so that won’t be easy to bed in quickly – and they won’t be the only changes made. They could need to replace 10-15 players and that’s down to bad management by the club, not by Neil.”

Cork-born Duffy had been living the dream when he signed for Celtic but it has turned into a living nightmare as the tenth successive title the fans craved has been meekly surrendered to Rangers.

Alan Stubbs explains why Shane Duffy has flopped for Celtic

“It’s been a horrendous experience for Shane and that’s not what he came to the club for,” Stubbs admits.

“He signed so that he could play regularly after being left out of the picture at Brighton and, at first, everyone looked upon it as a really positive move for Celtic and for him.

“Scoring in each of his first two games helped as well but, ultimately, it hasn’t really happened for him and there’s no point in me trying to say otherwise.

“I know Shane personally, having coached him when he was starting out. He’s a great lad and he has all the attributes – he’s big and strong, which is what you want from your centre-backs.

“But he’s looked vulnerable and confused and he started to over-think things because of the mistakes that he’d made.

“When that happens you try to do different things to show what a player you are rather than sticking to what you’re good at.

“If I’d been his manager I would have stripped everything right back to basics because he was doing things during matches which were baffling.

“There was one game where he’d been at fault for a goal and, minutes later, he was trying to do a [Cruyff] turn on the edge of his own box and that’s just not Shane.

“But that’s what mistakes and a lack of confidence do to you – they start to mess with your mind and, certainly right now, that’s what Shane is going through.”

Stubbs feels for his protégé but stresses that he is far from the only reason for Celtic’s failures this season.

“Only he can pull himself out of this and, in fairness, he’s not the only one not performing,” he said.

“It’s been a problem for him a) because the team hasn’t been in great form and b) results haven’t been good enough.

“He’s come to Celtic in what is going to be their worst season in ten years and that doesn’t look great. This was a huge campaign and one which offered so much hope before it had started.

“What they achieved beforehand – nine in a row and the quadruple treble, which will probably never be equalled – was incredible but the Holy Grail was the ten and that’s gone.

“Rangers have been good but they’ve not been brilliant. However, they’ve answered the questions asked of them while Celtic haven’t answered any of them.”