Celtic boss Neil Lennon has admitted that captain Scott Brown may be out until next year.
The influential Bhoys midfielder has a broken foot, which looks set to sideline him for six weeks.
He missed Scotland's loss to Czech Republic on Friday and he is also sidelined for the clash with world and European champions Spain on Tuesday.
And Celtic boss Lennon is desperately disappointed to be without him for such a sizeable length of time.
"Scott's injury is a big blow because he's pivotal for us. His performances have been good this season and we're concerned about the length of time he'll be out," said Lennon.
"We don't know the full extent of the injury. Hopefully we'll find out more this week.
"We're not sure how long he'll be missing but he'll be running the guts out of 12 weeks anyway."
Brown could not hide his disappointment after being sidelined, saying: "I'm really devastated. I'll be out for six weeks at least and I'm seeing a specialist on Tuesday to see if it could actually be longer than that.
"No player wants to sit out, especially me. I'm not one for sitting in the stands. I want to be involved.
"There are so many vital games coming up for Celtic and Scotland and I'm gutted I won't be able to play."