Though Cooper said "stranger things could happen," Callahan missed Game 6 against the Montreal Canadiens on Tuesday night. His absence meant the Lightning were 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.
"Naturally it's a blow to our team. But one guy doesn't make a team," Cooper said. "That's where you need your depth and you need guys to step up."
That somebody on Tuesday night was Jonathan Marchessault, one of the Lightning's so-called "Black Aces" called up to skate with the main group Tuesday morning.
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.
"I think the last game of the (regular) season I had a good game here," Marchessault said. "So hopefully I can go on the same pattern and just be intense and be ready to play a playoff game here."
Marchesseault made his Stanley Cup playoff debut, but the Lightning also scratched Vladislav Namestnikov to dress Nikita Nesterov and go with 11 forwards and seven defencemen. It's a look Cooper likes.
"It can take some minutes away from some of your defencemen, you can put situational defencemen in," he 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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