The player expected to be taken first overall in the upcoming NHL draft will have an MRI exam this weekend, according to agent Igor Larionov.
No timetable has been set for his return.
Yakupov was injured during Russia's 1-0 overtime loss to Sweden in Thursday's gold-medal game at the world junior championship.
The 18-year-old finished the tournament with nine assists in seven games.
He's among the top scorers in the Ontario Hockey League with 21 goals and 53 points in 26 games for the Sting.