The NHL Department of Player Safety has clarified why it decided not to suspend Vegas Golden Knights defenseman Zach Whitecloud for a hit that injured Toronto Maple Leafs forward Matthew Knies on Wednesday night.

The department released a video Thursday that covered three recent hits that involved contact with an opponent's head, the one by Whitecloud and two that resulted in suspensions.

Player Safety rarely addresses hits that don't result in supplemental discipline -- its last "explainer" video is believed to have been released in 2018. But Whitecloud's hit on Knies was a point of controversy in Toronto, in the media and among Leafs players.

In the second period of Toronto's 3-0 win at home Wednesday night, Whitecloud stepped up and checked Knies as Knies carried the puck over the red line. Whitecloud's skates left the ice on contact. The hit was reviewed by the on-ice officials who determined it didn't warrant a major penalty. Whitecloud was given a minor penalty for roughing. Toronto's Simon Benoit was given a double minor for roughing after going after Whitecloud. The referee's announcement infuriated the Toronto crowd, as Vegas earned a power play after Knies' injury.

Benoit said after the game that "I don't think it's a good call" and that "his feet were off the ice when he hit [Knies] right to the head."

The Player Safety video reiterated the two standards that need to be met for a violation of Rule 48, which covers illegal checks to the head: that the head was the main point of contact, and that head contact was avoidable.

The video contrasted the Whitecloud hit with checks that earned Toronto forward Ryan Reaves a five-game suspension and Los Angeles forward Tanner Jeannot a three-game ban for making contact with the head. Player Safety said there was "inarguably head contact" by Whitecloud, but that his hit went through the body of Knies rather than making the head the main point of contact, as Reaves did on Edmonton's Darnell Nurse and Jeannot did on Vancouver's Brock Boeser.

"We see Knies's entire body stopped in its tracks and driven backwards simultaneously with his head in a way that indicates the body absorbed the force of this check," the department said, adding that Whitecloud's hit was "legal within the framework" of Rule 48.

Player Safety also said Whitecloud took "a good angle of approach" on Knies, and that he didn't elevate "excessively or unnecessarily to pick the head" when he left his skates on contact.

"This means that the head contact is considered unavoidable on a play where the hitter is otherwise throwing a legal full body check," the department said.

Leafs coach Craig Berube said Thursday that Knies was doing "not bad" while still being evaluated by team physicians. "But he's feeling OK today, which is good news," he said.

As far as the hit by Whitecloud, Berube defended its legality.

"I mean, it's a hockey hit. It's been around forever," he said. "It's a clean hit. It's a tough play. He's in a vulnerable position a little bit. The guy was on him from behind and it's a tough play. But it's hockey. That's part of the game. The league's going to make judgment calls on all kinds of different hits like that. We've got to move on from it."

Knies, 22, has 12 points in 20 games for the Leafs, helping to bolster an offense that's been without Auston Matthews since Nov. 11 with an undisclosed injury.