The Leafs were scheduled to practice in Vancouver on Friday, ahead of Saturday's road game against the Canucks, but the team is erring on the side of caution and practice has been cancelled.
The COVID-19 situation across the NHL continues to intensify, which may force the NHL's hand and warrant another pause. With the highly transmissible Omicron variant, the league should be playing it as safely as they can.
As of this point, the game against the Canucks has not been postponed, but I would assume that if the Leafs end up reporting more cases, the NHL may have no choice.