Muzzin was not feeling right after yesterday's practice, per Sheldon Keefe. Muzzin has since been diagnosed with a concussion that will put him on the shelf for at least a week.
Muzzin is the second top-4 defender currently sidelined for the Leafs, with Justin Holl being the first. Holl is still in COVID protocol and could be out for tomorrow's game against the Rangers.
The Woodstock, Ontario native's concussion is believed to have been suffered during Saturday's game against the St. Louis Blues after he was hit by Klim Kostin on a play that lead to the Blues' 3rd goal.
It says a lot about the league considering that nobody spotted the concussion during the game and Muzzin was able to go about life as normal until after Monday's practice.
Hopefully Muzzin has a speedy recovery and can get back to contributing to a blueline that has been bombarded with injuries and COVID-related absences this season.