This is the fourth concussion Bergeron has suffered in his career.
"It's prescribed as 'moderate,' and I talked to him about an hour ago. He was in very good spirits," Chiarelli said. "He was out walking today. He was annoyed at it. He was emotional last night. I don't know when you'll see him again. You'll see him again, but I don't think you'll see him tomorrow. He sounded really good, and I told him we'll work together in getting him back."
During the second period of Boston's 3-2 win against the Senators on Tuesday night, Bergeron collided with Ottawa's Colin Greening and fell to the ice. Bergeron was slow to get to his feet before skating off the ice. He did not return.
"I won't have any further update until I have some significant information, but long story short, he got hit in the back, below the ear, and he said his neck is very sore. That's as much as I know," Chiarelli said.
After Chiarelli learned of Bergeron's injury Tuesday night, the GM considered making a deal for another forward before Wednesday's trade deadline, but ultimately made the decision to hold tight. The Bruins will not need to recall a center from AHL-Providence because Tyler Seguin and Kaspars Daugavins both can play center, according to Chiarelli.
"When you see a player like Patrice go down, there's no way we're going to replace him. There wasn't that caliber player [available via trade], so I'm not going to go around chasing it all day," Chiarelli said. "You've seen it across the league, teams have picked up the rest of the team when they have injuries, and I would expect us to do the same."
Chiarelli couldn't say whether this will be a long-term injury for Bergeron.
"I don't know," the GM said. "He was in good spirits. This is a few times we've been through this with Patrice, and to me, it doesn't [seem long term] just by how I talked to him and how he responded. But I can't speculate on it. These things are different in each case."
In 35 games this season, Bergeron leads the Bruins in scoring with 10 goals and 21 assists for 31 points, including a plus-23 rating.