The suspension comes after Hartman slammed down Senators' center Tim Stutzle's (23) head to the ice during a faceoff.
A meeting with league officials and Hartman took place on a Zoom call Monday after he refused their offer to do an in-person hearing.
"Hartman contends that he is attempting to use his hand to regain his balance using Stutzle for support, and that their fall to the ice is accidental," said a league official in an explanation video. "We disagree."
The lengthy suspension comes after Hartman has six previous incidents and four fines on his record. He has two days to appeal the suspension. The Wild's forward has seven goals and 10 assists in 48 games this season.
This now marks the longest suspension in the NHL since Washington Capitals forward Tom Wilson was suspended for 20 games in 2018.
Wilson's suspension was ultimately reduced to 14 games but there's no word as of now if Hartman will receive the same. If he doesn't win the appeal, the earlier he can return is March 6th due to the upcoming 4 Nations Face-Off.