The Boston Bruins have lost their clutch seventh-game performer Nathan Horton for the remainder of the playoffs.

Bruins general manager Peter Chiarelli announced Tuesday that Horton suffered a "severe concussion" as the result of the shoulder-to-head hit administered by Vancouver Canucks defenceman Aaron Rome in the first period of Boston’s 8-1 win on Monday night.

The Bruins released the news at about the same time Rome began his hearing with acting NHL disciplinarian Mike Murphy on Tuesday morning.

Rome received a four-game suspension for the hit.

"Two factors were considered in reaching this decision," Murphy in a statement. "The hit by Rome was clearly beyond what is acceptable in terms of how late it was delivered after Horton had released the puck and it caused a significant injury."

Horton, who has twice scored winning goals in Game 7s this post-season, against the Montreal Canadiens and Tampa Bay Lightning, was hit head-on. He was looking left at the direction of his pass when Rome delivered his late hit.

Horton was alert and had movement in all his extremities. He even tried to fight the trainer and get up after the hit. Instead, he was taken off the ice on a stretcher and transported via an ambulance to nearby Massachusetts General Hospital to be examined. He was held overnight in hospital for observation.

Rome was given a five-minute major for interference as well as a game misconduct. He missed the final 54 minutes and 53 seconds of the game.

Horton had eight goals and nine assists this post-season for Boston, which trails 2-1 heading into Game 4 on Wednesday night. He ranks second in the NHL post-season with a plus-11 rating, and skated alongside centre David Krejci and Milan Lucic on the Bruins' top line.

"The initial emotion would have been anger, probably," Bruins forward Shawn Thornton said. "I was worried and wanted to make sure he was okay.

"We talk about it all the time as players. That's the [type of hit] we got to get out of the game — head shots, blindside. I mean, that's what the rule is there for, so I got to see the replay and I don't think that stuff is warranted.

"That's on us as players. It is out of our hands now, but I think it needs to be addressed because there's too many of those things going on."

Thornton was asked how can this sort of head shot could be eliminated.

"By not hitting each other in the head," he replied.

Interestingly, the NHL’s new chief disciplinarian Brendan Shanahan and his blue-ribbon committee will make its first report on possible amendments to the year-old blindside headshot rule at the general managers meetings in Boston on Wednesday.

Although the Bruins did not score during the five-minute power play, the controversial hit sparked a four-goal outburst in the second period from Boston and a high level of animosity between the two teams.

A total of 145 penalty minutes were called, 75 to the Bruins. It was the second-highest penalty minute total in a final. The highest was the 176-minutes handed out in a 1986 game between the Montreal Canadiens and Calgary Flames.

Two incidents that angered Bruins coach Claude Julien were when his own two players, 43-year-old veteran Mark Recchi and Milan Lucic, acted like teenagers. Recchi put his finger to the lips of Max Lapierre in the first period to mock a similar move the Canucks forward did in Game 2. Lucic followed suit with a version of his own to Alex Burrows’s face in the third period. It was Burrows who bit the gloved finger of Boston’s Patrice Bergeron in the series opener.

With files from The Associated Press