Krejci will not play in Game 6 after sustaining a lower-body injury in the first period of Game 5 on a low hit from Senators defenseman Chris Wideman.
The Boston forward has no points in three games in the series after he had 54 points (23 goals, 31 assists) in 82 games in the regular season. He will be replaced in the lineup by Matt Beleskey.
2. Battle fatigue
It took 4 hours, 6 minutes for the Bruins and Senators to settle Game 5, and now they'll face off less than 48 hours after the start time Friday.
"I think most of the guys probably had a pretty good sleep [Friday] night," Senators forward Mike Hoffman said. "Guys that needed treatment will get it today, and tonight once we get into Boston, we'll gear ourselves up for [Sunday]. But it definitely will be a mental test for [Sunday's] game."
Bruins defenseman Kevan Miller was one of nine players to exceed 30 minutes of ice time in Game 5.
"Everybody's kind of feeling the minutes, whatever it may be," Miller said. "It's that time of year, and they're not easy minutes. But that's why we have days off in between, to rest and make sure everybody's rested and ready to go."