As Celtic prepare to take on RB Leipzig in the Champions League at Parkhead this evening, one notable selection headache for manager Ange Postecoglou will lie in midfield, with skipper and regular starter Callum McGregor facing an extended period on the sidelines.

The Scotland international sustained a knee injury in last week's defeat in Saxony, ensuring that the 29-year-old is set to be absent over the next month or so, seemingly ruling him out of action until after the upcoming World Cup.

Having to be without a simply irreplaceable figure - as Postecoglou stated - is far from an ideal prospect for the Hoops, with it yet to be seen just who will slot into that deeper role at the base of the midfield against Marco Rose's side.

The likes of Oliver Abildgaard and James McCarthy could well be potential answers to that problem, while summer signing Aaron Mooy is another who can line up in that playmaking role, albeit while having made just two starts in all competitions so far this term.

With the 32-year-old also only just returning from injury, an alternative solution could see Matt O'Riley take on a slightly deeper role in the side - as he did so against St Johnstone at the weekend - allowing new addition Sead Haksabanovic to keep his place in the side in midfield having impressed in Perth.

The former Rubin Kazan man - who arrived in Glasgow on a five-year deal in the recent window - notably played a key role in the visitors' opener in that victory over Callum Davidson's side, having seen his cross turned home by opposition defender Andy Considine.

The 23-year-old had looked "sharp" throughout Saturday's win - in the words of journalist Josh Bunting - recording an impressive pass accuracy rate of 91% to showcase his quality in possession, while also demonstrating his defensive strength as he won six of his seven ground duels.

That stunning display saw the £4.95m-rated ace receive a match rating of 7.7, as per SofaScore, with that by far the highest of any player on the day for either side, with the 30-cap gem having looked truly "dangerous" in his creative berth, according to journalist Sean Martin.

Also lauded as a 'constant menace' by Glasgow Live's Ben Banks, Haksabanovic has begun to show signs of his undoubted quality having been eased into life at Celtic Park thus far, with now potentially the time to secure a more consistent run in the side moving forward.

The forward's previous European start of the season against Shakhtar Donetsk had seen him look "very lively", as per Bunting, despite being withdrawn at half-time, with the player perhaps deserving of another chance to impress this evening.