Rask suffered the injury at 9:01 of the second period while making a save against the New York Islanders last Saturday at TD Garden. He fell to the ice in pain and needed to be helped off. At the time, the score was tied at 1-1, and the Bruins eventually lost 3-2.
Rask is 11-8-3 with a 2.05 goals-against average and a .929 save percentage in 23 games this season.
With Rask sidelined, the Bruins recalled goaltender Michael Hutchinson from the Providence Bruins of the AHL. At the time of his recall from Providence, Hutchinson was 6-11-0 with a 2.62 goals-against average and a .920 save percentage.