ALL good things must come to an end. And in truth, the love affair between Celtic and Leigh Griffiths has been petering out for quite some time.

In terms of sheer talent, Griffiths is among the most gifted finishers in Scotland. He has served Celtic well on the pitch when his career at the club is viewed over the course of his 256 games to date, scoring an impressive 122 goals in that time.

It is now over seven years since Griffiths joined Celtic though, and it has to be wondered just how many more appearances he could have made and how many more goals he could have scored had his professionalism not let him down on more than a few occasions.

In the last couple of seasons in particular, Griffiths has found rebukes from his managers over his conditioning easier to come by than starts for Celtic, even if he still finds his way to goal easily enough when he does work his way back into their favours.

Problems with his fitness are nothing new. Ronny Deila was the first manager to publicly question Griffiths’ commitment, lecturing him on the need to become a '24 hour athlete' back in 2015. As has been a pattern with the forward, he responded well, and went on to find perhaps his best form in a Celtic jersey under the Norwegian.

"If you look at me beforehand, still doing daft stuff off the field, and I've kind of quietened down a bit now and I had to because I was almost staring the exit door in the face,” Griffiths reflected later that year. His new found focus led to 40 goals in all competitions in the 2015/16 season, and he swept the board when the end of season awards were given out, scooping the PFA Scotland, Scottish Football Writers' and Scottish Premiership Player of the Year awards.

The arrival of Brendan Rodgers initially saw Griffiths remain a key component of the Celtic attack, but the arrival of Moussa Dembele and then injury problems saw his game time curtailed somewhat during the ‘Invincibles’ season. Indeed, Griffiths has failed to make more than 25 league appearances for Celtic in any season since 2015/16, and has scored just 36 league goals in that whole time period as a result, just five more than he scored in that one season alone.

Grace must be given of course over the lengthy spell Griffiths spent out of the game dealing with personal issues, and he is to be admired for the way he has overcome those problems in order to return to the spotlight of top-level professional football. Unfortunately though, his physical condition hasn’t always been compatible with that level.

"Players must be the very best they can be,” said Rodgers when addressing the issue with his forward. “Diet, nutrition & a full time professional mindset. To be a Champions League player you need to do this.”

The departure of Rodgers coming when it did seemed to favour Griffiths, with the striker having worn his patience to breaking point. The arrival of Neil Lennon back at the club was a further boost, being the manager who signed him in the first place.

Lennon was sympathetic to Griffiths and was desperate for him to find his best form once again. He was repaid by the striker turning up to pre-season training last summer overweight, with Griffiths himself admitting he was ‘a disgrace’.

He was left behind for a trip to France, and despite the odd burst of form here and there, he has been off the pace for much of the season. With Lennon now gone, Griffiths has emerged from the bench just twice under John Kennedy, in the 84th minute of the game against Dundee United, and in the 88th minute of the Old Firm derby.

“I’ll keep battering the doors down to show I am good enough to stay in the Celtic squad,” said Griffiths once, but despite his knack for proving his doubters wrong over the years, it would be quite the turnaround if he was to salvage his Celtic career from here.

With the departure of Celtic captain Scott Brown to Aberdeen as player/assistant manager in the summer, the rumour mill has been in full swing in these past few days that Griffiths is set to join him at Pittodrie.

Celtic seem sure to hang fire on letting any more players leave until their new manager is appointed, and Griffiths still has a year left on his Celtic contract. He will no doubt feel he can make his critics eat their words all over again, but regrettably, it feels as though this would be the perfect time for a fresh start.

If a deal could be done, it would seem to be a move that would make sense for all parties.

A focused and fit Leigh Griffiths still has plenty to offer, but there is no evidence to suggest that he can produce that level on a consistent enough basis to meet Celtic’s demands.

The Celtic supporters will thank Griffiths for the memories, but alas, it is time for everyone to move on.