Brassard appeared to injury his back, according to ESPNNewYork.com's Katie Strang. There was no immediate update from the team.
The hit came in the first period, and Brassard was slow to get up. The team's medical staff looked at him on the bench before he headed to the locker room.
The 26-year-old is in his first full season with the Rangers after coming to New York in a midseason deal that sent Marian Gaborik to Columbus last year.
A Quebec native, Brassard has four goals and three assists in seven postseason games. SI WIRE: Penguins fire general manager Ray Shero