Chara might need surgery, according to the source. He suffered the injury in the first period of Thursday's 3-2 loss to the Islanders and did not return to the game.
Chara's last shift came with 8:13 remaining in the first period. Earlier in the shift, he put a big hit on the Islanders' John Tavares between the circles in front of Bruins goaltender Niklas Svedberg. Chara did not appear to be injured and finished the shift before going to the locker room.
The Bruins' defensive unit already is down one man with Kevan Miller out indefinitely with a dislocated right shoulder.
Information from ESPNBoston.com's Joe McDonald was used in this report.