IT is not difficult to see just what it was that enticed Dedryck Boyata to Celtic this summer.

A quick glance at the metamorphosis enjoyed by compatriot Jason Denayer would surely have been enough to persuade him to turn his back on Manchester City after nine largely fruitless years and throw in his lot with the Scottish champions. A season at Parkhead evidently did Denayer no harm at all.

Like the before and after pictures in those adverts for slimming tablets or hair restoration treatments, the transformation in the 19-year-old defender was dramatic. He arrived as a teenage hopeful from the City reserve team, his path to the first team blocked by the likes of Vincent Kompany, Martin Demichelis and Eliaquim Mangala. He left Scotland a year later, his profile enhanced by a regular diet of domestic and European football, the PFA Scotland young player of the year award, and medals from his part in Celtic's triumphs in the league and League Cup.

Such has been the extent of his rise that he will begin this season with a real chance of playing in the City first team and as a full Belgian international. For that, Celtic and Ronny Deila can take a large share of the credit.

Now Boyata craves something similar. The pair's backgrounds are strikingly similar - both Belgian central defenders who couldn't break through at one of the richest clubs in the world - with the only real difference being that Boyata is five years older and has elected to sever ties entirely with City by signing a permanent deal with Celtic. Most importantly, like Denayer, he needs regular first-team football and a chance to feel wanted again.

"He needs love," was how Deila put it in his own idiosyncratic way, with the Norwegian giving the young talent the assurances he needs.

Perhaps unsurprisingly for someone who once trained as a teacher, one of Deila's key strengths is an ability to reach out to people on an individual level to bring the best out of them.

It will be a big ask for Boyata to replicate the immediate success Denayer enjoyed at Celtic - he even scored on his debut - but Deila saw sufficient potential and ability in his new signing to invest both time and money in him. He expects the subsequent rewards to make the effort worthwhile.

"He's an athlete, he's quick and very good on the ball," he said of Boyata. "He's also tall and good in the air. He just needs love, trust and opportunities to play. Players have to deserve that, so they have to show it in training and matches. But when you feel you are fourth choice and don't get any minutes [on the pitch] then you're just there and you don't feel the love you need. I know that if we can get the best out of him, he has the potential to be a top international player.

"The way we work, we have good material to work with. Jason was a very, very good player and Boyata is going to be good as well. I told him what we were capable of, we really believe in him and that he could be a great defender."

In some regards, Boyata and Denayer have swapped positions. Last year Celtic inquired about the former but were rebuffed as City still wanted to hold on to him. They took Denayer instead. Now the teenager's stock has risen to the point that Celtic cannot get him back. Boyata, though, had become dispensable to City and Celtic seized their opportunity.

"It's not easy to play your way into the Manchester City team when they can buy players for £35 million," added Deila. "It's tough but he's played [six appearances] this year for a fantastic team. The reason why City have spent money on him and tried to get him through is because of his ability. But the pressure is so tough at City. The level is very, very high. There are no youngsters coming through there. Here is a better stage for him as the level of the league isn't as high as it is in England."

Deila, whose side play their first pre-season game against Den Bosch at St Mirren Park on Wednesday, does not intend to make any more signings this summer. His preference would be to reduce his squad size by persuading fringe players to move on.

"We want a smaller squad so we can get youngsters in to train with us from our academy. It's important to develop the club that way and if you have too big a squad, there's no future for them. It's hard for me to see them every day and give them what they need as well. Without the goalkeepers, we maybe want to be at a total of 21 or 22. That's evolution, and we have to maybe take one more window to get to that number. But we're very clear on what we want and we'll see how quickly we can do it."