The Canucks, who will complete a six-game road trip when they play Maple Leafs, have lost two of three but are 9-4-1 in their past 14 games.
"It was a good game," Green said. "I thought we figured they'd come early, come hard at us, and they did. And I wouldn't say we weathered it, I thought the first period they probably had the upper hand a little bit, and we had a lot of time in their zone the last 34 minutes of the game."
Pettersson was face down on the ice after he fell awkwardly when his legs got twisted with Montreal forward Jesperi Kotkaniemi.
"Two guys who get tangled," Green said. "I've watched it a lot of times. First of all, it's not a dirty play by their player at all. He gets hooked a little bit, [Pettersson] actually pushes back on him and leans back and probably tries to give him a little bit of a reverse hit, and two young guys fall to the ice."
Pettersson, 20, completed his first NHL hat trick in overtime against the Senators after being named to the 2019 Honda NHL All-Star Game before the game.