After a slow start to the Stanley Cup Playoffs, the Boston Bruins' penalty kill has been nearly airtight from the second round on.

Heading into Game 4 of the Eastern Conference Final against the Pittsburgh Penguins Friday (8 p.m. ET, NBCSN, CBC, RDS) at TD Garden, the Bruins have killed off 26 of 28 power plays since the start of their second-round series against the New York Rangers.

Now the penalty kill will have a challenge almost as great as trying to stop Sidney Crosby, Evgeni Malkin and the rest of Pittsburgh's star-studded power play.

Center Gregory Campbell is done for the rest of the postseason with a broken fibula. He usually combines with fourth-line partner Daniel Paille to form one of Boston's three main pairs on their penalty kill, which ranked fourth in the NHL during the regular season.

"It's tough. He plays such a hard game," forward Brad Marchand said of losing Campbell. "He's such a big part of our team. You saw the last couple of rounds, he's been very big. He's not really a guy you can really replace, but everybody has to step up a little bit and hopefully, collectively we can fill that void."

Paille, Marchand, Patrice Bergeron, Rich Peverley and Chris Kelly will get the bulk of the Bruins' penalty-kill time. Kaspars Daugavins is scheduled to replace Campbell in the lineup, according to coach Claude Julien, and he has previous experience on the penalty kill.