The Belgian centre-back limped off in some discomfort just seconds before half-time in the Hoops’ pre-season friendly draw with Slavia Prague on Tuesday.
Now reports from his homeland say he is likely to miss the next six weeks of action.
Belgian newspaper La Derniere Heure claims Boyata ruptured knee ligaments and is definitely out of their opening tie with Northern Irish champions Linfield in Belfast a week on Friday.
If Brendan Rodgers’ men progress, Boyata will face a race against time to be fit for the potential play-off round clashes, with the first leg scheduled for August 15-16 and its reverse fixture a week later.
Boyata has bounced back to make himself a key figure in the Celtic line-up after enduring a difficult first season in Glasgow.
But Hoops boss Rodgers will now have to rely on the likes of Erik Sviatchenko and Jozo Simunovic as he plots a return to the group stages.