Pavel Zacha, Casey Mittelstadt welcome playoff challenge after welcoming babies

There's chemistry, and then there's "becoming new dads at the same hospital a day apart" chemistry.

The Boston Bruins' second line now has the latter. Left wing Casey Mittelstadt missed the Bruins' regular-season finale on Tuesday because his fiancee, Tatum, gave birth to their son, Macklin, that day.

Center Pavel Zacha played Tuesday, but only made it one period before he got the call that his wife, Gaby, was going into labor. Their daughter, Penelope, arrived early Wednesday.

Two linemates. Two first-time dads. Two babies just a day apart. Oh, and they were at the same hospital, too. By the time the Bruins regrouped for Thursday morning's practice after a day off Wednesday, Zacha and Mittelstadt's families were just three rooms apart at the hospital. They drove together from the hospital to Warrior Ice Arena for practice Thursday morning.

"I saw Macklin yesterday, so it was really cool," Zacha said. "Now we’re three doors down. So, it was really nice that we could both be there and experience the same thing."

"It was really cool," Mittelstadt said. "Obviously, it's gonna be a good story to have. Kind of funny to end up there at the same time."

It feels fitting that the bond between Zacha and Mittelstadt now includes this once-in-a-lifetime experience, because they've been connected on the ice all season on the Bruins' second line, along with right wing Viktor Arvidsson.

It's a second line that started the season as a major question mark, but now enters the playoffs as a major strength.

Zacha, Mittelstadt and Arvidsson were all coming off down years. Mittelstadt (at last year's trade deadline) and Arvidsson (over the summer) were both essentially salary-dumped by contenders (Colorado and Edmonton, respectively) who no longer considered them a fit. Zacha faced questions about whether he could produce on a line that didn't have David Pastrnak on it.

The trio answered those questions and silenced their critics in emphatic fashion. They played 585 minutes together at 5-on-5, third-most of any trio in the NHL. Their plus-20 goal differential during those minutes was tied for second-best among all NHL lines, trailing only Colorado's top line of Nathan MacKinnon, Martin Necas and Artturi Lehkonen.

Zacha scored 30 goals for the first time and registered a career-high 65 points. Arvidsson's 54 points were double what he had last year in Edmonton, while playing just two more games. Mittelstadt, a former top-10 pick who was viewed as an all-offense, minimal-defense type of player, proved his two-way reliability while shifting full-time to the wing.

Bruins coach Marco Sturm came to trust the trio so much that he used them as his shutdown line, matching them up against opponents' top lines throughout the season. That they continued to produce like one of the league's best offensive lines was the cherry on top.

"That line has been a massive boost, injection for our club, on both sides of it," general manager Don Sweeney said Tuesday. "Very well trusted from a defensive standpoint, but their production was paramount to one of the reasons why we're here."

The "here" is the Stanley Cup playoffs. The Bruins will begin their best-of-seven first-round series Sunday in Buffalo against the Sabres. The time of Game 1 is still to be determined, as is the schedule for the rest of the series.

Zacha, Mittelstadt and Arvidsson will remain a go-to line for Sturm. They will see plenty of the Sabres' stars – Tage Thompson and Alex Tuch on the top line, and/or dynamic Norris Trophy candidate Rasmus Dahlin on the top defense pair.

It's a challenge they're ready to embrace.

"As a player, I think you want to be the guy," Mittelstadt said. "You want to be out there in those moments, and you want to play on a line that has to do a big job and be a big part of it. I think we've done a good job of that this year, so of course you want to be out there, and we're looking forward to keep doing it."