VANCOUVER, British Columbia >> The last thing the reeling San Jose Sharks need as they try to close out December on a positive note is an injury to one of their top-pair defensemen.

But the Sharks went into the Christmas break without veteran Jake Walman, who sat out Monday’s game with the Vancouver Canucks at Rogers Arena with a lower-body injury.

Sharks coach Ryan Warsofsky said Walman was injured during Saturday’s game against the Edmonton Oilers and is now considered day-to-day as the team begins a three-day holiday break.

The Sharks host the Vegas Golden Knights on Friday in Tomas Hertl’s first game back at SAP Center since San Jose traded him in March and the Calgary Flames on Saturday.

“We’ll see how the next few days go, but he’s day-to-day,” Warsofsky said of Walman, who worked out off of the ice as his Sharks teammates went through the morning skate.

Walman finished with 25:51 of ice time in that game and assisted on Jan Rutta’s first-period goal, but was also on the ice for the last two Edmonton goals, as the Oilers scored late in the third period and 18 seconds into overtime to earn a 3-2 win.

The loss of Walman is a considerable one for the Sharks, who had lost four straight games and seven of their last eight before Monday.

Acquired from the Detroit Red Wings in June for future considerations, Walman leads all Sharks defensemen with 25 points, including 20 assists, is a significant presence on both the power play and penalty kill, and leads all team skaters in average time on ice (22:50).

The Sharks were also without Walman for five games in early November and went 2-2-1 in his absence. Walman was sat out for one game for violating a team rule for not coming in to get treatment for an injury on an off-day and for four others as he recuperated from that injury.

“Can break out pucks, is obviously a really good skater, can get out of our own end, defends with a purpose, helps on our power play,” Warsofsky said of Walman. “So we need some guys to step up tonight.”

To start Monday’s game, Henry Thrun took Walman’s spot on the left side of Cody Ceci on the Sharks’ top defense pair.

Thrun was a healthy scratch for recent Sharks games against St. Louis, Utah, and Winnipeg but dressed for the last two games, at home against Colorado and in Edmonton, in a third-pair capacity.

“I thought he put his two best games together here as of late,” Warsofsky said of Thrun. “So he’ll get the first crack at that spot with cease, and we’ll go from there.”

Thrun averaged 14:37 in ice time in those games against Colorado and Edmonton but had an opportunity to take on a bigger load on Monday, like he did last season when he averaged 20 minutes per game. In 29 games this season before Monday, Thrun had eight points, all assists, and averaged 15:58 per game.

“Obviously, my goal is to be a guy that can play in the top four and play against first and second lines,” Thrun said Monday.

BACK IN NET: >> The Sharks started goalie Yaroslav Askarov for the second straight game Monday after he made 41 saves in a brilliant performance against the Oilers. Askarov went into the game against the Canucks with a 1-0-2 record this season, a .928 save percentage and a 2.20 goals-against average.

LINE CHANGE: >> Warsofsky shook up his forward lines for Monday’s game, most notably moving Mikael Granlund to the wing on the top line with Macklin Celebrini and Tyler Toffoli. Granlund has been a centerman for most of this season, but the Sharks were searching to boost an offense that has scored just 20 goals in its last nine games, including 15 at even-strength.

“Our defense and our coverage needs to be a little bit better, but we also have to drive some offense, so that was kind of the reason behind moving (Granlund) to the wing,” Warsofsky said. “Get someone to play with Macklin there a little bit.”

“Mack can really make some plays,” Granlund said. “I can try to help with that and play some good hockey, and (Toffoli’s) a really smart player. He’s going to find those scoring areas. Just have to defend hard and we’re going to get our chances offensively.”

With Granlund moving to Celebrini’s wing, Nikolai Kovalenko started the game on a line with Luke Kunin at center and Fabian Zetterlund on the right wing. The second line featured Alexander Wennberg at center and William Eklund and Will Smith on the wings.

The Sharks also had Nico Sturm, Ty Dellandrea and Barclay Goodrow on the fourth line, meaning Carl Grundstrom was a scratch.

KOSTIN’S STATUS: >> Sharks forward Klim Kostin was optimistic earlier this week that he could come off injured reserve and be available to play against the Canucks. Kostin skated again Monday morning, but his upper body injury will get at least three more days to rest and heal.

“I think it was close today, but not there yet,” Warsofsky said of Kostin coming off IR. “So we’ll circle back after the break.”

Kostin was injured in the Sharks’ game in St. Louis on Dec. 12 as he hit Blues forward Brayden Schenn and got into a skirmish with Dylan Holloway. Schenn had just dished out big hits on Granlund and defenseman Mario Ferraro.

Before his injury, Kostin had dressed for 13 of the last 14 games and played some of his best hockey of the season, as he had with four points in eight games to finish November.