Patrice Bergeron has been diagnosed with a concussion and placed on injured reserve. He was released from Massachusetts General Hospital on Sunday.
The Bruins' centre left in the second period of Saturday's game against the Hurricanes after a collision with the Canes' Dennis Seidenberg.
In a statement, Bruins GM Peter Chiarelli said the 23-year-old's condition "has improved greatly over (Saturday) night" but added that there is no timetable for his return.
This is not unfamiliar territory for Bergeron, who missed the majority of last season with a concussion.
The Quebec native has 4 goals and 14 assists in 31 games so far this season.