When Celtic have dominated games against Rangers in recent years, invariably, Callum McGregor has been the man running the show. When Rangers have managed to get some success against Celtic, it is because they have been able to find a way to nullify, or at least lessen, his influence.

It is little wonder then that Celtic are so desperate to get their captain on the pitch at Ibrox this weekend, despite the fact that he hasn’t played since coming off at half time in the 7-1 demolition of Dundee in late February.

What was billed as a precautionary measure to protect an Achilles issue then has turned into a lengthy absence, and while Celtic have largely managed to limp by – save from a 2-0 defeat at Tynecastle where they felt with some justification that refereeing decisions went against them – they are a different beast with McGregor at the heart of their side conducting proceedings.

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McGregor can sometimes fly under the radar, and in fact, has often been on the end of criticism this season for his performances. But his best match of the campaign was the defeat of Rangers at Celtic Park in late December, when he was imperious in a vital 2-1 win for the champions. Prompting quite the appraisal of his performance from manager, Brendan Rodgers.

“What an amazing player,” Rodgers said.

“Wow. You can be so proud of that kid.

“I have seen two versions of him. When I was first here I had seen him grow and develop into a really important player for me. He was a player I would have taken anywhere when I left here, he was so good. To be able to come back and have him as my captain, I am very, very lucky.

“He is just an absolutely brilliant player, on a different level - with the greatest of respect – to everyone else on the pitch. His view of the game, his quality, when to slow the game, when to pick up the tempo. He’s absolutely brilliant.

“I am so happy for him because it is so important as the Celtic captain in these games to perform and he has done that now in the two games we’ve had against Rangers.”

Celtic’s chances of a third win over their great city rivals his term, and what would be the most crucial victory yet, would certainly be greatly increased if McGregor was to make it.

There is no doubt whatsoever that his importance in such matches is recognised within Celtic Park, and there is even less doubt that McGregor will be pushing to play, even if he isn’t quite at one hundred percent.

This is the man, after all, who strapped on a face mask 11 days after sustaining a double fracture to his cheekbone at Alloa to lead his side to victory over Rangers in a similarly pivotal fixture a couple of years back.

Any concerns over his stamina levels after a few weeks out are legitimate enough on the face of it, with former Rangers captain Lee McCulloch expressing doubts this week about the wisdom of McGregor being thrown into such a fixture as ‘it’s not as if you can pace yourself’ in an Old Firm game.

True enough, but given McGregor’s general fitness levels and his consistent capacity to manage over 60 games a season over the past few years, that is perhaps not quite as major a concern as it might be with other players.

That may well have been wishful thinking on McCulloch’s behalf, with the Rangers supporters just as keenly aware of McGregor’s potential to tip this contest away from their team as anyone on the other side of the city.

Steven Gerrard eventually twigged onto that fact too, and while the fluctuating fortunes of each team during his time at Ibrox have to be taken into account, some of the success he enjoyed in the games between the sides in the latter days of his reign was predicated on flooding the midfield and crowding McGregor out.

You just have to witness the exasperation of the Rangers fans as former manager Michael Beale allowed McGregor the freedom of Govan in the first fixture between the sides this season to know that they fully appreciate how vital it is to shackle him.

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Philippe Clement didn’t manage it in his first Old Firm game at Celtic Park, with the apparent tactic of dropping Todd Cantwell onto the Celtic captain having little to no effect on McGregor, and in fact, leading to a rather comical sequence as he easily held off Cantwell as he repeatedly nipped at his heels.

Surely, the reborn John Lundstram would be a better option to take on the task this time around, bringing his energy, strength and greater defensive qualities to the party.

So, the outcome of the game might not solely boil down to whether McGregor makes it or not, but if he has any chance of lining up at Ibrox, Celtic have to take the risk. And Rangers, for their part, simply have to find a way to stop him.