The Islanders were leading 4-2 at the second intermission with Rask allowing four goals on 16 shots. The Islanders ultimately won the game 5-4 to take a 3-2 series lead.
After the game, Bruins head coach Bruce Cassidy said the decision to pull Rask was not performance-related.
“There was some maintenance that needed to be done. He wasn’t 100 per cent," Cassidy said, according to ESPN's Greg Wyshynski. "He wasn’t himself. He could have been back in. We made the decision not to put him back in.”
Rask missed Monday's morning skate and has been dealing with an unknown ailment during the playoffs, but had not missed any game-time up to this point.
“Game feels good. Health is OK,” Rask said in an appearance on The Greg Hill Show ahead of the series. “I’ve been playing, so that’s OK. It’s not as good as I’d want it to be, but obviously I’ve been playing and practicing. I’m out there. That’s all that matters.”
Entering Monday night, Rask has posted a 6-3-0 record with a 1.94 goals-against average and a .935 save percentage during the 2020-21 post-season.
The Bruins also announced that forward Curtis Lazar suffered a lower-body injury on Monday and would not return to the game.
The Islanders can eliminate the Bruins with a win on home ice in Game 6 Wednesday. It's unclear for now if Rask will be healthy enough to start for Boston.