LAS VEGAS — San Jose Sharks centre Joe Thornton has been suspended for one playoff game for a hit to the head of Vegas' Tomas Nosek.

The NHL's Department of Player Safety said that Thornton's hit on Nosek in Game 3 was avoidable and that the head was "clearly the main point of contact." That led to the decision to suspend Thornton for Game 4 on Tuesday night in Las Vegas.

Thornton was called for an illegal check to the head on the play and defended it after the game.

"I honestly thought I barely touched him," Thornton said after the game. "He just came right back; it was just one of those plays that it is what it is. I think my son hits me like that six times a day, it's just a weird position to put himself in, that's all."

The Golden Knights felt otherwise about the hit in the second period of a 6-3 victory that gave them a 2-1 series lead.

"It's gutless," Vegas forward Ryan Reaves said. "It's behind the play. It's to the head. It's everything you're trying to get rid of in hockey."

Thornton's last suspension came in November 2010, when he was banned for two games for a head hit to St. Louis' David Perron.

Thornton is a key piece in San Jose's lineup, centring the third line alongside Marcus Sorensen and Kevin Labanc and also playing on the top power-play unit. He has one goal and two assists in the series.

The Sharks could be without two other players with shutdown defenceman Marc-Edouard Vlasic listed as day to day with an upper-body injury that sidelined him for Game 3 and fourth-line wing Micheal Haley questionable after leaving Game 3 after blocking a shot with his ankle.

This marks the second straight year that a Sharks player was suspended for a playoff game against Vegas. Forward Evander Kane was suspended for Game 2 last year for a cross-check to the head of Pierre-Edouard Bellemare.