The incident occurred at the end of Toronto’s 3-0 win at Edmonton on Monday night. Chiasson was assessed a major penalty and game misconduct for cross-checking. Chiasson will forfeit $18,534 in salary.
The Maple Leafs and the Oilers will finish a three-game series Wednesday in Edmonton.
Toronto won the first two by a combined 7-0 score, and both games were played without the Maple Leafs leading scorer, Auston Matthews.
The Associated Press contributed to this report.