Celtic midfielder Callum McGregor's injury is a 'huge' blow for Ange Postecoglou, according to former Hoops and Scotland striker Frank McAvennie.

The Lowdown: McGregor suffers injury

Postecoglou's side suffered a disappointing night in the Champions League on Wednesday, losing 3-1 away to the Bundesliga side RB Leipzig.

The result wasn't the only negative in Germany, however, with McGregor forced off during the first half through injury, adding to Celtic's woes through the spine of the team with Cameron Carter-Vickers also struggling recently.

Ahead of this weekend's clash with St Johnstone, Postecoglou admitted that the issue for his midfield masetro 'doesn't look good', with the Scot now set for a spell on the sidelines.

The Latest: McAvennie bemoans news

Speaking to Football Insider, McAvennie couldn't hide his disappointment regarding McGregor's injury, admitting it is a 'huge' blow:

"They have definitely not got anyone like Callum, losing him is huge.

“I heard someone say last night, and it is so simple that a lot of people will not get it, he plays all the hard balls, which are the easy ones. He just keeps the ball easy whereas everyone else tries to hit 30 yard passes, he just keeps the ball rolling.

"You miss him because of his composure in midfield. Hopefully it is not going to be too long. Even in the second half when he was on they were getting run over the top of. Abildgaard, after a couple of games, I think he could be a decent player.

"It is a dilemma for Ange but I am hoping he is not going to be out for long. It was certainly noticeable against Leipzig."

The Verdict: Will be a big loss

McGregor has been such a great performer for Celtic over so many years, winning seven Scottish Premiership titles and being described as 'outstanding' by Postecoglou, so this is undoubtedly a big setback.

His leadership and quality in the middle of the park will be much missed during what a busy run of fixtures for the Hoops, with others needing to step up in his absence.

The hope is that McGregor is back in the fold sooner rather than later, however, having a major say on Celtic's title defence and Champions League campaign.