NHL's Brendan Gallagher Viciously Elbows Opponent's Head, Fans Demand Suspension

Brendan Gallagher was ejected from the Canadiens game Thursday night for throwing a vicious elbow at his opponent's head ... and now, fans want to see him sidelined for a while for the dirty play.

The incident happened during the Canadiens' game against the Islanders at the Centre Bell Arena in Montreal ... when Gallagher tried to stop Adam Pelech from getting deep into the neutral zone.

Video from the game's broadcast shows right as Pelech crossed the blue line ... Gallagher elbowed him in the face -- sending the defenseman crashing to the ice.

Pelech stayed down for a while -- although he was eventually able to skate to his team's locker room. He did not return to the game. Gallagher, meanwhile, was ejected for the illegal check.

Puckheads were furious over the play ... rushing to social media to demand a lengthy ban for Gallagher. Even the right winger's former teammate, P.K. Subban, said the 12-year NHL vet needs to be suspended.

"I don’t know how else I’m supposed to call that," Subban said about the collision, "but to me, those are the hits that we just can’t have. That’s just inexcusable. There’s no upside."

This isn't the first time Gallagher has made a move like this on the ice ... in November 2021, he punched Barclay Goodrow, and was fined $2,500.