"It's not too bad. Probably as good news as we could have hoped for," Green said.
Pettersson sat out Saturday's game after hurting his right knee Thursday night against the Montreal Canadiens. In that contest, he went down awkwardly after getting tangled up with fellow rookie and Canadiens forward Jesperi Kotkaniemi.
Pettersson leads all first-year NHLers with 22 goals and 42 points. He was named to the Pacific Division All-Star team on Wednesday.