Eller has been released from the hospital after being treated for a concussion and facial fractures sustained in the second-period hit in Game 1 of the Eastern Conference quarterfinal series, the Canadiens said Friday.
Eller had taken an ill-timed pass up the middle from defenseman Raphael Diaz when he was flattened by Gryba.
In its explanation of the suspension, the NHL's Department of Player Safety cited a violation of Rule 48, which outlines illegal checks to the head. Gryba's mistake was making "Eller's head the principal point of contact, causing a serious injury."
"We do not see malicious intent by Gryba on this play," the explanation video said. "Eller is eligible to be checked and Gryba does not extend an elbow or launch into the head. However, Gryba's route is not correct, and we do not feel that he made enough of a full-body check not to qualify as an illegal check to the head."
Eller was removed from the ice on a stretcher and hospitalized after losing consciousness. He had fallen face-first to the ice, knocking out teeth and resulting in a pool of blood. The league said it took Eller's injury into consideration when deciding punishment.
Gryba was assessed a five-minute major for interference and a game misconduct for the hit.
"I stepped up to make a hit. I kept my shoulder down. He received the puck by the time I hit him," Gryba said after the game. "I saw the replay. My elbow was down and there was no intent to hurt him whatsoever and I hope that he's OK. I'm not out here to hurt anybody and it's never good to seeing anything like that. I hope he makes a full and speedy recovery."
Senators coach Paul MacLean defended Gryba's hit after the game.
"It was a hockey play," he said. "Our guy hit him, but player 61 [Diaz] is the guy to blame."
Canadiens forward Brandon Prust took offense with MacLean's comments.
"We don't really care about what that bug-eyed fat walrus has to say," Prust told the media, according to TSN.ca.
Canadiens coach Michel Therrien also called MacLean's words "an inappropriate comment."
"No respect for the player on the ice who was bleeding, not respect for his family in the stands. ... This is why we have new rules to avoid those hits," Therrien said Friday.
The NHL called Diaz's pass "completely irrelevant to whether or not Gryba delivers a reckless, illegal check to the head."
The Canadiens won Game 2 on Friday night, 3-1, to even the series at 1-1.
Information from The Associated Press was used in this report.