Callum McGregor is a legendary Celtic captain in the making but he needs midfield help to add a new chapter in his storied career - Tony Haggerty

“Celtic jerseys are not for second best, they don't shrink to fit inferior players.”

These are the words of legendary Celtic manager Jock Stein. It was a rare sight indeed for McGregor to finish second best in a Celtic shirt last season. All sorts of accusations were flung his way in the last campaign - he was no longer the player he once was, he had lost his midfield mojo. There were even ludicrous suggestions that McGregor had run his race at Celtic and that it might be better for both parties if he started a new chapter elsewhere. All nonsense of course.

New Australian boss Ange Postecoglou knew exactly who to turn to when he walked through the famous glass doors at Celtic Park and searched for a captain. Steady leadership - check. A role model of excellence - check. Composure and control personified - check.

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The Scotland midfielder ingratiated himself even further to the Celtic supporters in the aftermath of the 6-0 drubbing of Dundee last month in the first home Premiership match of the season. McGregor gathered the players together for an impromptu huddle at the END of the contest which the Celtic supporters lapped up.

He explained thus: "What I said to the players will remain private, but it is just good to show the togetherness. A lot of new players were experiencing Celtic Park for the first time in a league match, a good performance, a good result.

"It is just important that they feel the importance of winning at Celtic Park in style and we just continue to work ever so hard in training, we perform as best as we possibly can in games and we try to send the supporters home happy every week if we possibly can.

“But, like I said, it was just a show of togetherness. We always thank the fans for their support, win, lose or draw and we will always do that.”

Another transfer window has come and gone and whilst the club did some tidy business in certain key areas, three overarching questions did spring to mind. What would happen if there was an injury to McGregor and who would step up to the plate for Celtic in that case? 

The facts are that McGregor is second to none in terms of consistency. He has played 371 matches for Celtic and scored 53 goals. Look at these stats for minutes played in the last five seasons - 5,072, 4414, 5563, 4791, and 4,732. Incredible stuff.

In 2020, McGregor featured in the top ten for most minutes played. He kept esteemed company alongside Lionel Messi, Harry McGuire, Romelu Lukaku and Raphael Varane. Postecolgou knew his value to the team which is why he has deployed McGregor in the sole sitting or pivot midfield role. Some experts have started the role is akin to the Quarterback position in American Football.

Whatever way you look at it, McGregor is still Celtic's best midfielder whether he is deployed in a deep-lying role or in a more advanced position. He has a keen eye for a goal and a pass in the final third whenever he moves forward.

Since McGregor has moved to play deeper he has been nothing short of inspirational. Whether under pressure or not McGregor has been the go-to man and the out-ball for 'Angeball' when receiving it from the likes of Joe Hart or any member of the defence. He oozes confidence, composure and self-assuredness.

Yet he remains one injury away from throwing Celtic into disarray. Think Andy Halliday's challenge on the opening day of the season at Tynecastle. This makes it all the more baffling as to why Celtic did not think of adding to their squad in that area during the window to offer cover or simply to protect their star man from playing so many games.

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Celtic did sign James McCarthy, the 30-year-old former Everton and Republic of Ireland midfielder but little has been seen of him since his arrival in Scotland and he was injured for the AZ Alkmaar and Rangers matches.

McCarthy can certainly mix it but it is debatable as to what role he is best suited to. Is he an anchor or does Ange see him as someone capable of being more forward? Does McCarthy fill that void if there is no McGregor? Then why give McCarthy a four-year deal if that was not the case? Will this be a position that Celtic do strengthen in January from the J-League that Ange has alluded to? The importance or indeed relevance of McCarthy's signing has yet to be seen for Celtic. 

For all David Turnbull is lauded as a fantastically talented footballer - and he most certainly is - he failed to cover himself in glory in two crucial matches against AZ Alkmaar and Rangers. He most certainly wasn't involved enough for Ange's liking in both games.

It certainly looks like the manager has also made up his mind on Ismalia Soro and before too long the Ivorian could end up being Celtic's forgotten man. Despite playing with the likes of attack-minded players such as David Turnbull and Tom Rogic, if McGregor were injured then Ange clearly does not trust Soro to be the midfield pivot.

All of these things further serve to highlight McGregor's invaluable contribution to the cause as well as the glaring deficiencies within the squad.

Now one player Celtic could have snapped up in the August transfer window and who could possibly perform the CalMac role is St Johnstone's Ali McCann. The Northern Ireland internationalist was linked with a move to Celtic but ended up signing for English Championship side Preston in a £1.2 million deal. McCann, who won both the League and Scottish Cup with the Saints last season, seemed like the ideal candidate as a midfield reinforcement.

He was absolutely superb for the Perth side in their recent Europa League outings against Galatasaray. Surely, McCann was the kind of player that could have stepped into the CalMac role if and when required. He could also have offset the huge burden of expectation placed on McGregor's shoulders this season.

Perhaps the most surprising aspect of Celtic's transfer business in the August transfer window was that no Scottish players were signed. For some unknown reason, Celtic remain light in terms of quality midfielder players with Ryan Christie now having departed. The threadbare nature of Sunday's bench at Ibrox was a case in point.

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Only Tom Rogic was a potential game-changer among all the substitutes listed. It begs the question of whom Celtic turn to if and when McGregor doesn't play this season through injury, suspension or fatigue?

The problem, for now, is that McGregor's role and position have become so crucial to their fortunes - especially the way the team now plays under Ange. Whilst CalMac has proven to be a revelation the need for Celtic to have a midfielder ready to step in when he is not there seemed glaringly obvious. By failing to add another quality midfielder in the McGregor mould during the transfer window both Celtic and Ange will be hoping and praying they have not dropped the ball on this issue.

The importance of McGregor's functionality in the Celtic team may have been temporarily lost in the past 12 months. Nobody is doubting McGregor's captain or leader qualities now. CalMac is currently working on his legend status.