SAN JOSE — The Sharks on Sunday were dealing with the possibility they may be without their steadiest defenseman for their biggest game of the season so far.

Marc-Edouard Vlasic, injured in the first period of Game 5, did not practice Sunday and is questionable for Game 6 of San Jose’s Western Conference quarterfinal series against the Los Angeles Kings on Monday. The Sharks lead the series three games to two.

The Sharks boarded a flight to Los Angeles on Sunday afternoon, and as of a few hours earlier, coach Todd McLellan said he did not know if Vlasic would make the trip. “We had a meeting, we had a quick practice — I’ve got to go deal with that as the next thing,” McLellan said. “Obviously he didn’t skate today, so he may make the trip and we’ll see how he is tomorrow.”

Vlasic, who has played in all 84 Sharks postseason games since his 2006-07 rookie season, left the ice at 14:09 of the first period after Kings center Jarret Stoll checked him into the boards. On the play, Stoll’s right knee appeared to hit hard into the back of Vlasic’s left leg. After that, Stoll’s right forearm connected with the back of the Vlasic’s head.

Stoll received a two-minute minor penalty for roughing on the play, but as of Sunday afternoon there was no indication there would be any supplemental discipline from the NHL.

Vlasic’s absence left a huge void Saturday, as the Sharks were outshot by the Kings 41-30 and had trouble cleanly getting the puck out of their own zone for most of the game.

“He’s a guy that plays a lot of minutes for us, and he’s a very steady player,” McLellan said Sunday. “We have other players that we can put in there. Matt Irwin and (Matt) Tennyson have been waiting for their opportunity, and if need be, they can go in and I’m sure they’ll give us the game that we need from them.”

If Vlasic is unavailable, the Sharks most likely would turn to Irwin, who had 20 points in 62 games this regular season. He also played in all 11 of the Sharks’ playoff games last season, including the seven-game second-round series against the Kings. Tennyson does not have any playoff experience.

“If I play tomorrow, I’m ready to go,” Irwin said. “It’s the playoffs, right? So anytime you get an opportunity, you want to make the most of it.”