Celtic have been dealt another potential injury setback ahead of next week's clash with Motherwell, with promising midfielder David Turnbull having been forced to pull out of the Scotland squad.

What's the word?

As per national team coach Steve Clarke - via the Scottish Sun - the 23-year-old has withdrawn from the international set-up with an ankle issue, having reportedly sustained the problem during the Hoops' loss to St Mirren on Sunday.

Following the playmaker's absence from the Nations League victory over Ukraine on Wednesday evening, Clarke revealed: "David Turnbull will pull out the squad. He picked up an ankle knock at the weekend that we thought would clear up. It's not going to clear up in time for us.

"He's better to go back to his club to get ready for their next game. Two players light, I'll probably need to call up at least one, maybe two players."

Postecoglou should be gutted

That will come as a real concern to Parkhead boss Ange Postecoglou, with the 57-year-old already potentially without a handful of key names ahead of the return to league action at the start of next month, when the Old Firm outfit will be looking to bounce back from that recent defeat in Paisley.

That dismal display saw the Scottish champions lineup without the defensive pairing of Carl Starfelt and Cameron Carter-Vickers, with the "immense" duo - as dubbed by pundit Chris Sutton - both currently sidelined with injury.

With those issues already handing the title-winning coach a possible headache for the upcoming clash with Steven Hammell's side, the loss of Turnbull will only exacerbate the concern, with Postecoglou likely to be gutted at potentially losing such a valued squad asset.

While the former Fir Park starlet has been in and out of the side so far this term as a result of the exceptional form of fellow playmaker Matt O'Riley - who has five assists in just seven league games - the £5.85m-rated man has still made an impact when he has featured, scoring once and laying on three assists in all competitions to date.

That solitary strike notably came in the 4-0 thrashing of bitter rivals Rangers a few weeks ago, with the 6 foot 1 ace capitalising on a goalkeeping blunder from Jon McLaughlin to add late gloss to the scoreline.

The youngster had previously impressed during last season's title triumph, proving himself a real potent threat in the final third as he chipped in with 18 goal contributions in all competitions, having matched that tally in his debut campaign a year prior.

With fixtures set to come thick and fast over the next month or so, Postecoglou would likely have been keen to call upon such an impactful asset - even if only off the bench - with it now an anxious wait to see if Turnbull can be fit to face his former club in just over a week's time.