JOHN Collins has told Leigh Griffiths he needs to get back into the shape he was in when he netted 40 goals for Celtic during the 2015/16 campaign in order to successfully resurrect his career.

Griffiths returned to training at the Parkhead club at the tail end of last season after taking an extended break from football to deal with personal issues.

The 28-year-old is hoping to be available for selection when Neil Lennon’s side play their first Champions League qualifiers next month.

Collins, who worked with his fellow former Hibernian man during the two years that he spent as assistant to Ronny Deila, is hoping Griffiths can put this difficult spell firmly behind him.

The ex-Celtic, Monaco, Fulham and Everton midfielder always found the striker to be completely professional – despite rumours to the contrary.

However, he believes the Scotland internationalist must work on his physical condition if he is to be the scourge of defences both in this country and abroad next term.

HeraldScotland:

READ MORE: Neil Lennon: Having Leigh Griffiths back next season will be like Celtic signing a £6 million striker

Asked about the suggestions that Griffiths didn’t train under Deila, Collins said: “That’s not true at all. That’s the lightest he has ever been. How many games did he play? He wouldn’t have been playing if he wasn’t training. Those were the rules.

“I had no problems with him, I used to work most days after training with him. We’d work on his finishing and if you ask any striker that’s what they enjoy doing most with any coach.

“I had the fun part. When myself and Ronny were there he had the most successful season of his career, 40 odds goals. It was a good time for him, but we can’t take any credit, he has to take that himself.

“He was banging in goals all over the place, but he had to wait for his chance, he had to work hard to get in the team. He got himself fit and sharp and when he’s like that he’ll score goals in any company.

“Like most footballers, he needed to be told the truth sometimes and sometimes the truth hurts. Other times he needed a cuddle but then all footballers are the same.”

“Most players understand that to stay at the highest level it takes sacrifice. It takes dedication and you get your rewards.

“You take your foot off the gas and if you’re not professional as you should be - be it eating, drinking, sleeping or even training properly - then that’s when the problems start.

“You can be the best player in the world but if you don’t have your fitness then you won’t perform. You need to take care of yourself, that’s not just exclusive to Leigh.

“I have said it 100 times, Leigh has a lot talent. The hardest thing in football is to score goals and he knows how to score goals. He has to learn that you need to be fit and dedicated to play 50 or 60 games a season.

“The last few seasons he has not been able to do that. So he has to take a long look at himself and ask the questions to the guy in the mirror.”

HeraldScotland:

READ MORE: Celtic striker Leigh Griffiths set for phased return

Collins added: “You have got to feel for him and you have got to hope that he can get himself back on track. For his own sake first and foremost, but also for Celtic’s sake and Scotland’s sake too.

“When he’s fit and healthy he’s a threat, he’s a quality striker of that there is no doubt. I have seen him smashing them in from all angles with that left foot of his.

“So fingers crossed he can put his troubles and his injuries behind him and get back doing to what he does best. He needs to get into that Celtic side and then back into that Scotland jersey”

John Collins was speaking at Hampden this week a year before Euro 2020 kicks off. Ticket applications for UEFA Euro 2020 are now open at euro2020.com/tickets.

Hampden Park will play host to four matches on June 15, 19, 23 and 30, 2020. Be part of it!