WHATEVER else Ronny Deila has done, he has left Celtic at a crossroads, and in the absence of words of wisdom from chief executive Peter Lawwell and majority shareholder Dermot Desmond, it has to be speculated that the long-term future of the club will be decided in the next few weeks.

Deila was to have been that future. Only last May, Lawwell was admitting that appointing the unknown Norwegian had been a gamble.

His exact words were: “Though some would think we took a risk, which we probably did, we felt he was an ideal candidate for Celtic and he fitted really well with our strategy, which is to create a winning, entertaining football team, to create football players, to create a team, a backroom staff and develop players.”

There’s the rub. It was far too much to expect all of that from a novice manager at a club the size of Celtic where aspirations coloured by a glorious past are always above a realistic level.

Deila’s main problem was that he came with fixed ideas of the kind of players he wanted and how he required them to play the game, and in his first season he did reasonably well with Celtic playing some fine football at times – no more so than on the night they came from two down to draw 3-3 with Inter Milan.

Yet a draw, even against genuine giants of the game, is never enough for Celtic and in his second season Deila seemed to forget that, playing almost a safety-first system with just one attacker up front. Fortunately, that was Leigh Griffiths who repaid Deila’s faith in him with a barrage of goals.

The number of times he varied that system could be counted on the fingers of one hand, and it was that rigidity and inflexibility with tactics and players which has characterised his time at Parkhead.

He also set himself up for a fall – he it was who preached that his players had to be super-fit, yet on Sunday it was Rangers who looked the fitter team, because even the fittest need rest and the likes of Scott Brown, Mikael Lustig and Nir Bitton did not get enough.

Deila also made it clear the domestic treble was his aim after exiting Europe, and that target did not survive the League Cup semi-final against Ross County. Aiming high and finishing low is a recipe for disaster. Always giving the impression of calmness, especially when facing the press, Deila may well have been concealing turmoil within the camp, and possibly even within his staff. No one has yet broken ranks to say so, but when the likes of Anthony Stokes, Kris Commons and James Forrest find themselves out of favour, something had to be wrong in the mix at the Lennoxtown training camp.

The manager also has to take the rap for poor signings: Peter Lawwell’s name is on the contracts, but it is Deila who had the final say on the hiring of a pile of duds, frankly. The only unmitigated success among the 23 who put pen to paper in Deila’s time has been Craig Gordon – and he came free.

Erik Sviatchenko showed against Rangers what he can do if he stays injury-free, and Deila was also unlucky to lose the services of Jozo Simunovic to injury. Had those two been the central defensive partnership from the start on Sunday, the result would surely have been different. Other injuries at key times to the likes of Scott Brown and Charlie Mulgrew, plus loss of form of Stefan Johansen, Stuart Armstrong and Gary Mackay-Steven did not help the Norwegian much either.

But let’s throw out just a few names – Stefan Scepovic, Saidy Janko, Michael Duffy, Nadir Ciftci, Carlton Cole, Scott Allan, Ryan Christie … remember them? And let’s not mention the loanees, like Alexander Tonev, Tyler Blackett and Wakaso Mubarak – failed short-term fixes for long-term problems.

For that is what cursed Deila and meant that he was fighting a losing battle after his first season – just as some players could not fit into his system, so he could not “do” the Celtic system.

Celtic need to find and develop young players to sell them on at a profit – it’s been their business model for some years now, and Fraser Forster, Victor Wanyama, and Virgil van Dijk alone made more than £30 million profit for Celtic

Deila couldn’t find their like to any extent, Kieran Tierney and Callum McGregor are the youngsters who have made the biggest impression, and they are both home-grown.

So Deila goes with little or no playing legacy in place. Presuming Celtic do win the title, they will have a matter of weeks before next season’s Champions League qualification begins.

Is that enough time to bring in someone with a long-term vision of how the club should develop on the pitch, a diplomat who can deal with all sides at this fractious time while retaining the physical and intellectual strength required to do the job properly?

All of that and deal with a resurgent Rangers, too? The new incumbent will need to be a cross between Superman, Albert Einstein, Henry Kissinger, and – most of all – Jock Stein.

There’s not many of them about, not many at all, and the way ahead for Celtic seems treacherous right now.