Polak drove Bjorkstrand into the boards one minute into the third period after Bjorkstrand turned around to play a puck into the Toronto zone.
The 21-year-old had to be helped off the ice.
A five-minute major for boarding was called, and now the Leafs will have to wait and see whether the league finds the hit worthy of supplemental discipline. It will review the play Thursday morning.
Have your say on what the department of player safety should do below.