The incident occurred early in the first period. As Eriksson turned to follow the puck back up the ice while defending in his own zone, Orpik caught him while he wasn't looking with a high hit.
No penalty was called on Orpik for the hit. Eriksson immediately left the ice for the locker room, where he was evaluated for a concussion. The Bruins announced later that Eriksson would not return to the game.
It's another tough break for Eriksson in what has been a nightmarish first season with the Bruins. He already missed significant time earlier this year with a concussion after taking an illegal elbow to the head from Buffalo Sabres forward John Scott. Scott was suspended seven games. You can bet that Orpik will face some sort of league discipline for this hit as well.
UPDATE: The Bruins have confirmed what everyone feared.
Eriksson has a concussion. #Bruins— DJ Bean (@DJ_Bean) December 8, 2013