Kassian extended his leg toward Cernak's chest in the first period Thursday night. The Edmonton winger wasn't penalized for the incident.
The league offered Kassian an in-person hearing Friday morning, which allowed it to ban him for six or more contests. He waived his right to the face-to-face meeting - instead opting for a phone hearing Friday afternoon.
It's the second suspension for Kassian in 2020. The league handed him a two-game ban in January for his role in an altercation with Calgary Flames forward Matthew Tkachuk.
Kassian defended himself postgame, calling the incident "reactionary," but admitted he was trying to kick Cernak off him.
The league said that while it acknowledges Kassian's argument, it "in no way justifies this action."
The 29-year-old was handed two previous suspensions before this season, sitting eight games for high-sticking in September 2013, and serving a three-game ban for boarding in March 2014.