TAMPA, Fla. — Tampa Bay Lightning coach Jon Cooper knew when he got a call from head athletic trainer Tom Mulligan on Monday afternoon that it wasn’t good news. Ryan Callahan had some abdominal discomfort and underwent an emergency appendectomy.

Though Cooper said “stranger things could happen,” Callahan figures to miss Game 6 against the Montreal Canadiens on Tuesday night. His absence means the Lightning are without one of their most important forwards.

“You win with guys like Ryan Callahan,” Cooper said. “That’s why he’s another one that’s played so many playoff games in his career because you win with guys like that. We saw that the day he came here in the trade last year, and he’s done nothing but elevate the play of our team.”

Callahan has only three assists in these playoffs but hasn’t been on the ice for a goal against in the second round. He has played more at even strength than any Tampa Bay forward except for Alex Killorn.

“That’s where you need your depth and you need guys to step up,” Cooper said. “Ryan Callahan plays 15-20 minutes a night, somebody’s going to have to take those minutes and run with them.”

That somebody could be Jonathan Marchessault, one of the Lightning’s so-called “Black Aces” called up to skate with the main group Tuesday morning. Marchessault said he would take part in pre-game warmups.

The 24-year-old with four games of NHL experience, including two this season, last played in the AHL with the Syracuse Crunch on April 29. Marchessault has been skating with fellow backup players Mike Angelidis, Slater Koekkoek, Luke Witkowski and others to stay ready.

“If I get a chance to get in I want to show what I can do,” Marchessault said. “I think the last game of the (regular) season I had a good game here. So hopefully I can go on the same pattern and just be intense and be ready to play a playoff game here.”

Jonathan Drouin is also an option, though that seemed unlikely after the morning skate. The other option is playing Nikita Nesterov and going with 11 forwards and seven defencemen, something Cooper likes.

“It can take some minutes away from some of your defencemen, you can put situational defencemen in,” Cooper said. “You get a little parade to the penalty box with defencemen, you still got more guys back there.”

Cooper said Callahan checked out of the hospital Tuesday morning and that he was “feeling really good.” Doctors caught the problem before Callahan’s appendix ruptured, and captain Steven Stamkos said indications were everything went well with the operation.

If the Lightning lose, Game 7 would be played in Montreal on Thursday night. If Tampa Bay wins, Game 1 of the Eastern Conference final would be Saturday.

“We want to win and get a chance for guys in this room to get healthy, with Cally included,” Stamkos said.

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Stephen Whyno, The Canadian Press