WHEN Scott Brown made the decision to bring his Celtic career to an end last summer, the biggest question was not over how the club would fill his boots in the middle of the park, but over how they would fill the armband.

With Brown’s powers as a player fading during his final season at Celtic, it was the removal of his leadership that would leave the largest void in a squad that was set to undertake a massive overhaul.

Ange Postecoglou took his time to confirm the official appointment of Callum McGregor as the man to take on that task of replacing Brown, and the similarly formidable undertaking of helping mould an almost entirely new group of players into a cohesive unit. To help unify them around the common cause they had all been brought to Celtic for; to win back the league title.

They now stand on the brink of doing just that, and the leadership of McGregor has been a hugely significant factor in bringing them to this point. On Sunday, there was a moment that provided a perfect microcosm of why he has proven to be such an effective captain, and a leader through example.

With Celtic seemingly being blown off the Ibrox pitch in the early stages of the game by a rampant Rangers, McGregor took his teammates by the scruff of the neck, and the match as well by extension. He took it upon himself to drive forward into the Rangers area, eventually forcing the equaliser for his team and simultaneously knocking the wind out of their opponents and the stadium.

“Callum was just outstanding as a leader,” said Celtic manager Ange Postecoglou in the aftermath of his side’s eventual victory. “His role in that first goal, particularly, was brilliant.”

It was an example of the sort of leadership McGregor has been providing for this Celtic team all season. Rushing himself back from a double fracture to his cheekbone to take on Rangers at Celtic Park, just eight days after sustaining the injury at Alloa, was another case in point.

In difficult moments, he has stepped up to the plate, and when Ange Postecoglou’s team has been firing, it has been he who has invariably been at the centre of it all.

The remarkable thing about the way McGregor has grown so effectively into the Celtic captaincy is how he hasn’t allowed it to prove a distraction from his game. His level of play has remained at a consistently high level throughout the season, whether that has been in the deeper lying midfield role that is now his main area of operation, or in a more advanced position when the occasion has required.

He has previously admitted that it has not been as seamless a transition for him as it has appeared on the field, either in terms of adjusting to his new role as captain, or in adapting to his new position within Postecoglou’s team structure.

“It’s a different role within the team and within the squad as well, so I’ve been getting used to that, how to deal with the players and things like that,” McGregor said recently.

“But it’s been brilliant, it’s been something I’ve really enjoyed. I’m learning on the job all the time.

“The players have been first class, absolutely excellent in the way they’ve applied themselves all season, and then that makes my job easy as well.

“On my position, I’ve been playing a little bit deeper, getting a lot of the ball and starting a lot of the attacks as well, which is good.

“So it’s something I’ve really enjoyed as well, and it’s a big period coming up, so everyone just needs to stay on it 100 percent and hopefully by the end of the season we’ve achieved what we want to.”

That Celtic may be about to achieve more than anyone outside of their changing room felt possible in winning at least a Double, and perhaps even surpass their own expectations by making it a Treble, is down to more than just McGregor. Or even Postecoglou.

But there is no doubt whatsoever that the new Celtic skipper has played a massive role in making what had seemed to be hugely fanciful goals just a few short months ago a potential reality.

It would take a collapse of epic proportions over the final six games of the Premiership season for Celtic to cede their six-point, 16-goal advantage over Rangers at the top of the table. With McGregor’s quietly effective leadership, married to his knowledge of what it takes to win at Celtic, what now seems highly unlikely is the possibility that they will falter at the final step.

With the greatest of respect to Scott Brown and his achievements at the club, perhaps the biggest compliment that can be paid to McGregor is that Celtic have barely missed him in the first season since his departure.

There are other players throughout the division who have been hugely impressive too, with Craig Gordon enjoying a vintage season at Hearts, for example.

But for his exemplary play on the field, his influence on his teammates, and for his likely trophy haul at the end of his first campaign as Celtic captain, McGregor has to be Scotland’s player of the year.