It's feared that Callum McGregor could be out of action for a lengthy spell after suffering a suspected 'broken bone' against Alloa.
The Celtic skipper dook a dunt to the face during the Hoops' 2-1 Scottish Cup fourth round win over the League One side yesterday.
McGregor had to be withdrawn and ex-Celt Peter Grant is concerned he could be sidelined for an extended period.
The former Parkhead player suffered a facial injury of his own during his playing days and recalled that he wasn't back playing in a timely manner.
Key clashes against Hearts and Rangers are coming up for Ange Postecoglou's team and Grant doesn't think McGregor will be ready for them.
"At first everyone thought it was a head clash but my concern is when you seen Callum holding the side of his face," the former Dunfermline boss said on Sportscene.
"I've broken a bone there myself and it was six to eight weeks I was out.
"You look at the manager after that and it's the most disappointed I've seen him since he became manager, so you can tell Callum has picked up a bad injury."
Grant went on to suggest McGregor will be a huge miss.
"The way it was looking, the way he was touching the side and not the front (of his face), it could still be a broken bone," he added.
"It would be a huge loss for Celtic, for everybody yes, he's been a top player from them."
