David Krejci was a late scratch from the lineup with an upper-body injury. He participated in warm-ups then was scratched after a discussion with the training staff.
The Bruins are already playing with a depleted defense with both Torey Krug and Brandon Carlo out with injuries.
With Krejci out, Sean Kuraly made his postseason debut.
The 24-year-old Kuraly had one assist and 11 shots in goal in eight games for the Bruins this season.
Cox Media Group