With under 10 minutes to go in the first period, Simmonds went to hit McDonagh, and the Rangers D-man cross-checked Simmonds in the face.
Simmonds responded with a slash, and then punched McDonagh, who stayed down on the ice before leaving the game to be looked at.
Scotiabank Hockey Day in Canada Live: Latest articles, videos, social content
In the end, Simmonds received a match penalty for intent to injure, and was thrown out of the game, while McDonagh got two minutes for slashing, and two minutes for high-sticking.
The Rangers received a one-minute power play after the teams played 4-on-4 for four minutes. The team announced later that McDonagh would not be returning to the game.
#NYR Injury Update: Ryan McDonagh will not return this afternoon
— New York Rangers (@NYRangers) February 6, 2016
Under Rule 21 regarding match penalties, Simmonds will be suspended indefinitely until commissioner Gary Bettman reviews the play.