It took two injuries for that to happen, first Jonas Gustavsson's shoulder in November and then all-star Jimmy Howard's groin last Saturday. On Tuesday night in Buffalo, he made just his eighth career NHL start, which could be the first of many more starting assignments over the next few weeks.
"It's nice I will get a chance to play more," Mrazek said this week. "Growing up, what I (wanted) to be (was a) No. 1 goalie. It's not nice to see when Howie (got) hurt and (I) hope he's going to be back soon."
Coach Mike Babcock called Howard "week-to-week" and has gone back to his usual stance of putting injured players aside to talk about those who can be on the ice and in games. He's used to that from last season, when the Red Wings missed stars Henrik Zetterberg and Pavel Datsyuk for long periods of time and survived myriad injuries to make the playoffs.
Players are accustomed to it, too, which is why they can have faith in Mrazek, new backup Thomas McCollum or anyone in net.
"I just think that everybody steps up and tries to fill that void that we have or that role that you need to jump into," defenceman Brendan Smith said. "Everybody here is professional and they understand their role. I'm not worried about it. It's hard on a team when you lose your best players, but the door is open and somebody can jump in."
Gustav Nyquist busted the door down last season, going from minor-league call-up from the AHL's Grand Rapids Griffins to one of the league's most prolific scorers. At one point he had 23 goals in 34 games.
Mrazek doesn't have to steal the show like Nyquist, though on the day Dominik Hasek had his No. 39 retired by the Buffalo Sabres, Babcock said he'd love for the Czech native to be as "mentally strong and determined" as his idol.
The 22-year-old with just 21 games of NHL experience is ready for the challenge but doesn't intend on changing much of his routine.
"It's just a game and you have to be ready for every game you play if it's once a week or three games in a row," Mrazek said. "Just be ready and I do the same thing if I don't play or if I play."
The onus may be on Mrazek's teammates to change some things, or at least tighten up. Detroit is solidly in third place in the Atlantic Division with 55 points through 43 games, but much of that is thanks to Howard, who had a 2.11 goals-against average and .920 save percentage.
In Howard's absence, the Red Wings have to adjust to Mrazek.
"I think little things that we can do: We can talk to him more, we can kind of figure out our systems," Smith said. "He's a goalie that is aggressive and is very confident and challenges, and we love that out of him. We're really happy to play in front of him."
Happier, too, because Mrazek is such a strong puck-handler. Babcock told reporters in Washington over the weekend that the staff needs to settle the young goaltender down and keep him from challenging too much, but Detroit will take his puck-handling abilities with some of those things that have to be ironed out.
"He can be one of the better puck movers in the league," Smith said. "He does move the puck so well that he doesn't see as many shots because we're breaking out."
Mrazek saw 26 shots in beating the Sabres 3-1 Tuesday night. With no back-to-back games on the Red Wings' schedule for the foreseeable future, this could be the time to show what he can do.
Smith knows Mrazek well enough to be confident in his ability to hold down the fort until Gustavsson and Howard get back.
"When something happens, there's a door open and you've got to step up and kind of show that you belong here," he said. "That's something that the young Wings have done and it's pretty cool and I think Petr's been doing it. He's just got to keep staying on it, and I think he's going to keep getting better."
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