SAN JOSE >> Sharks defenseman Marc-Edouard Vlasic walked into the team’s practice facility Thursday morning and saw that he would be playing an NHL game that night for the first time in almost nine months.

“I saw my name on the lineup,” Vlasic said, “and I was pumped this morning.”

After missing training camp with an upper-body injury and spending the past several weeks building up his conditioning, Vlasic made his season debut Thursday when the Sharks played host to the Tampa Bay Lightning.

Because Vlasic was injured before the team’s training camp began in September, he had been designated by the Sharks as a non-roster player since the start of the regular season in October. Vlasic was moved to the Sharks’ active roster on Thursday afternoon and was expected to be paired with Jan Rutta for the start of the game with the Lightning and be a part of the team’s penalty kill.

In October, the 37-year-old Vlasic, now in his 19th NHL season, said that his injury mainly involved his upper back. But he had regularly participated in Sharks practices and morning skates since at least late November.

“I’m 100%. I’m ready to go,” Vlasic said Thursday. “Just happy I’m in and excited for tonight.”Still, Vlasic’s addition to the Sharks’ roster on Thursday was a bit unexpected.

On Wednesday, Sharks coach Ryan Warsofsky said Vlasic was still working on his conditioning and that the team was still building him up to play again. Asked explicitly if Vlasic might be ready to play again in the next couple of weeks, Warsofsky said, “It’s hard to say. I’d like to see him in some more practices, but we’ll see.”

“It’s building him up” to a place, Warsofsky said, where “we’re all comfortable with putting him in.”

In late November, Warsofsky said Vlasic could be activated during an upcoming six-game road trip that lasted until Dec. 12. But Vlasic’s status did not change until Thursday when the Sharks determined that Vlasic’s conditioning was finally up to par.

“There’s a lot of data that we look at with our sports performance staff,” Warsofsky said. “(There’s) the eye test. Does he execute when it comes to breakouts? There are some things that he’s done with (assistant coach) Doug (Houda) at the end of skates. So a combination of all those things.”

The Sharks created a roster opening for Vlasic on Thursday when they placed forward Carl Grundstrom on injured reserve.

Grundstrom was injured in the first period of the Sharks’ game against the Calgary Flames on Dec. 28 when he was hit in the neutral zone by defenseman Brayden Pachal. Grundstrom is eligible to come off IR on Sunday, but Warsofsky said it was too soon to say whether the Swedish-born winger, who skated Thursday, would be available to play again at that point.

Vlasic missed the first 40 games of the season as the Sharks entered Thursday with an 11-23-6 record. Having gone 1-10-1 since a 2-1 victory over the Washington Capitals on Dec. 3, the Sharks fell back into eighth and last place in the Pacific Division.

The Sharks hope Vlasic can become a stabilizing force on the back end.

Since that win over Washington and before Thursday’s game, the Sharks have given up an average of 4.08 goals per game, tied for the most in the NHL. Also, on Dec. 9, the Sharks traded their No. 1 goalie, Mackenzie Blackwood, to the Colorado Avalanche as part of a deal that brought goalie Alexandar Georgiev to San Jose.

Vlasic, for well over a decade, was considered one of the league’s top shutdown defensemen, a role he had in 2014 when he won a gold medal with Team Canada at the Winter Olympics in Sochi, Russia. While Vlasic’s ice time has dipped in recent years, and he was a healthy scratch on multiple occasions last season, Warsofsky is confident Vlasic can still provide quality minutes.

“I still think he’s got a really good stick. He can still close and kill plays,” Warsofsky said. “I think he’s still very responsible defensively and knows where he needs to go. He knows where goal scorers are going to go.

“So it’s not like he just forgot how to play the game. We believe in him to kill plays, break out pucks and be really good defensively for us tonight.”

Vlasic, drafted in the second round by the Sharks in 2005, played in his 1,297th career NHL game Thursday. He is second on San Jose’s all-time games played list, behind only Patrick Marleau (1,607).

Vlasic’s game Thursday will be his first since April 8, 2024, when the Sharks, who were without several veterans that night, lost to the Edmonton Oilers 9-2.

Asked if he feels he has something to prove at this stage of his career, Vlasic said, “No. Why should I? I’m in the lineup tonight. So, apparently, I can still play. If I couldn’t play, (Warsofsky) wouldn’t have put me in.

“I’m still playing in this league after 19 years. Gonna try to bring what I can bring. What I worry about is what I can bring to the team and help them win. The rest is out of my control.”

SHAKIR SITS >> With Vlasic returning, defenseman Shakir Mukhamadullin was a healthy scratch against the Lightning. Mukhamadullin had played in eight of nine games since he was recalled from the Barracuda of the AHL on Dec. 10, scoring his first career NHL goal on Dec. 27 against the Vegas Golden Knights and averaging 15:27 in ice time per game. Forward Ty Dellandrea was also a healthy scratch.

GRAF PLAYS >> Forward Collin Graf, recalled from the Barracuda on Tuesday, dressed for Thursday’s game and started on a line with fellow former NCAA stars Macklin Celebrini and Will Smith. Graf, who did not play Tuesday, signed with the Sharks in April as a college free agent after two seasons at Quinnipiac, which included a national championship in 2023.

Before joining the Sharks last season, Graf had 49 points in 34 games with Quinnipiac and was named a finalist for the Hobey Baker Award as college hockey’s top player. Celebrini won the award after his 64-point freshman season at Boston University. Smith led all NCAA Division I scorers last season with 71 points in 41 games at Boston College.