Juolevi was placed on injured reserve Wednesday, per CapFriendly.
Juolevi has yet to make his Panthers debut, so his undisclosed injury likely occurred during a practice session. The 23-year-old was traded to the Panthers from the Canucks prior to Opening Night. He'll be eligible to return next Wednesday versus the Bruins, but it's unclear if he'll be able to earn a spot in the lineup even once he's healthy.