RONNY Deila’s clear aim at the start of this season was to have a trimmed-down, finely-balanced Celtic squad of 22 players who were all good enough for the challenges which lay ahead.

That he ended up with a bloated group of players, some he did not want and others who were simply not up to it, is one of the main reasons why his team fell short over the campaign and that his stay in Glasgow is prematurely coming to an end.

Deila blames himself. It was he, the Norwegian claimed, who wanted the players that ended up as an unused substitutes or in the stands, and therefore the responsibility lies with him and nobody else.

Knowing how Celtic works, it is difficult to accept that the manager was the only person within the football club selling and buying players. Scott Allan, for example, did not fit into the team’s style of play, something Deila admitted. So why buy him at all then?

And why not leave Ryan Christie on loan at Inverness? Can anyone explain Nadir Ciftci, Carlton Cole, Tyler Blackett or Saidy Janko? Why are Anthony Stokes and Stefan Scepovic still on the books?

Even Billy Stark, former Celtic player, coach and officially football’s nicest man, said the squad was too big.

“I totally agree [with Stark] but I also had that issue when I came in here,” said Deila. “There were too many players at that time. There have been mistakes but we have taken chances with players, trying to find the right ones.

“When you don’t have a lot of money and you can’t get the ones you know are real quality, you have to take chances. In the end it has been unbalanced and that’s a challenge. It is a problem that has to be resolved.

“We had a very good unit here last year and also into the qualifiers, and then in Christmas. But after that we got stuck with too many players and that is my responsibility. There are things I should have done better.

“Different things have happened and we have done things that we shouldn’t have done – that’s something you learn from. I saw at the end of January we had too many players. Some of the players were injured and we couldn’t use them so we took on extra and in the end there were too many.

“Also we had people in on short notice as well – loan deals. Had we been involved in Europe and both cups it might have been different but it has been too many.”

Celtic might not be the biggest payers any more but it is the biggest club and most lucrative contract almost all of the current squad will have in their careers.

Blackett, for example, might go back to Old Trafford after his wretched loan deal has ended but he won’t be appearing in the first-team any time soon. This is a problem when it comes to pushing the unwanted out the door.

“It’s sometimes hard to move players on. You always wait to the last minute and things can go wrong because all the clubs want to get players in as cheaply as possible,” admitted Deila. “It will be up to the new manager to change things and do things he wants to do.

“Yes, I wanted to work with a smaller squad but that’s not the biggest factor here – it’s about quality in the end. I have spoken to Peter Lawwell and my staff about which players should leave and they have a good view of that.”

The sight of Allan in particular, sitting in the stand in his club suit, was hard to take. Deila, quite clearly, didn’t want him and so a genuine Scottish talent has missed an entire season of first-team football.

Deila admitted he felt sorry for those who could not get into the 18 man match-day squad and has felt the need to apologise to them over the past few months.

Which does beg the question: why sign the likes of Christie and Allan when they were never going to get even a glimpse of a game.

However, Deila said: “I know Ryan he will be a great success in the end. Scott has trained well. He has talent. He maybe didn’t suit the style I want to play but he can get in the team if it’s another style. So it’s up to them to show the new manager that they deserve to be in the team,

“I don’t think it was a mistake [to sign Allan], it is just that other players have been going well. There are a lot of players who haven’t played much in their first year and it’s a big step coming to Celtic from Hibs.

"He works hard and is a very good guy in the environment. He’s still a young guy. He has to develop and has the talent.

"You have to play almost on the Scottish national team to get a game and we had very few injuries this year so that’s also made it much, much harder for him to come in. It’s too early to judge him or anyone else.”

Deila has been judged not good enough to be Celtic manager. And yet a win against Aberdeen this afternoon will bring him a second title and there will be celebration.

He has had success. His problem has been that the failures always seemed to matter more.

“The Champions League is the important thing,” he said. “Important games, when we haven't succeeded or have been good enough, have affected the atmosphere in and outside the club.

“Now we are 99.99% sure we have won the league and so it is a very good situation for the club next year. A new manager with new ideas and energy will hopefully lift the club to where it wants to be.”