The Bruins said Thursday that Chara will travel back to Boston to be re-evaluated by team doctors.
The team was already without defensive stalwarts Charlie McAvoy (concussion), Kevan Miller (broken hand) and Brandon Carlo (upper body), as well as rookie Urho Vaakanainen, who sustained a concussion last month after being called up to fill in.
"It seems like we're losing a guy every game," goaltender Jaroslav Halak said. "We need to keep playing hard, and whoever comes in the lineup has to step up."
The injuries mean that when the Bruins play Friday in Arizona in the second game of their current road trip, 2015 first-rounder Jakub Zboril could become the third rookie defenseman to make his debut this season along with Vaakanainen and Jeremy Lauzon.
Zboril was called up earlier this week to serve as the extra defenseman on the trip.
The Associated Press contributed to this report.