Updated

BOSTON -- Nathan Horton will miss the rest of the Stanley Cup finals with a severe concussion and Canucks defenseman Aaron Rome is finished too after the NHL suspended him for four games Tuesday for his blindside hit on the Bruins forward during Game 3.

Horton had just passed the puck early in the first period when Rome lowered his shoulder and left his skates to flatten him, delivering what the Bruins saw as the kind of hit the league has tried to eliminate after several players sustained severe concussions.

The NHL wasted no time stepping in, either, quickly announcing Rome would not return to the series.

"Two factors were considered in reaching this decision," Mike Murphy, the league's senior vice president of hockey operations, said in a release. "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."

The 26-year-old Horton, the right wing on Boston's top line, apparently was knocked unconscious by the collision, hitting his head on the ice and staying down for several minutes while medical personnel attended to him.

He left Boston's 8-1 victory on a stretcher and was taken to a hospital.

"He's been a great teammate for us all year," said forward Mark Recchi, who scored two goals in Game 3. "It's tough to see your teammate down on the ice. We know it was late, but we're not in control of what the league does."

If the Stanley Cup is awarded before Game 7, the NHL said Rome's suspension will carry over to the start of next season.

The Bruins updated Horton's condition in a release Tuesday morning.

Horton has eight goals and nine assists this postseason for Boston, which trails 2-1 heading into Game 4 on Wednesday night. He's second in the NHL postseason with plus-11 rating, and he already became the first player in NHL history to score a game-winning goal in a Game 7 twice in the same postseason run.

He skates alongside center David Krejci and Milan Lucic on the Bruins' top line. Boston coach Claude Julien hadn't yet decided how to replace Horton after the Bruins' victory Monday night.

Horton has been a hero in the postseason for Boston, which is in the Stanley Cup finals for the first time in 21 years. Horton scored the winning goal in overtime in Game 7 of the first round against Montreal -- and again in the Eastern Conference finals, getting the only goal in Boston's 1-0 victory over Tampa Bay late in the third period.

Horton is in his first career postseason after spending his first six seasons with the woeful Florida Panthers. The former No. 3 overall draft pick has 168 goals and 180 assists in 502 games.

Horton was Boston's second-leading goal-scorer this season with 26, finishing fourth on the team with 53 points.

While Horton is a key offensive player for the Bruins, the 27-year-old Rome is a depth defenseman for the Canucks, usually playing in their third pairing. He has one goal and 37 penalty minutes in the postseason.

Vancouver already lost defenseman Dan Hamhuis to an undisclosed injury in Game 1 of the finals, but the Canucks are deep on defense, with veteran Keith Ballard sitting out the first three games as a healthy scratch.