Bergeron/By S. Bradley

WILMINGTON, Mass. — Bruins center Patrice Bergeron suffered a mild concussion last night in Game 4 of the Eastern Conference semifinal series with Philadelphia.

General manager Peter Chiarelli revealed that update today and said during a press conference at Ristuccia Arena that it’s a “safe assumption” Bergeron will not be available to the Bruins for at least the first couple games of the Eastern Conference finals with Tampa Bay, depending on when the series starts.

“I guess, anything can happen, but that’s the assumption I’m operating under,” said Chiarelli.

Bergeron was hit by Flyers forward Claude Giroux on the forecheck early in the third period of Boston’s series-clinching victory. The Bruins alternate captain skated off under his own power, but went straight to the dressing room. Chiarelli said Bergeron went to the NHL-mandated quiet room and took the modified SCAT test. Doctors then determined Bergeron could not return to the game.

Chiarelli said he hadn’t spoken to Bergeron, who went home last night, yet today. But after the game Bergeron was “a little despondent but he was quite lucid to me. He was despondent having suffered another concussion. But he was just OK.”

Doctors told Chiarelli that this concussion was less serious than the one he suffered in a collision with then-Carolina defenseman Dennis Seidenberg in December 2008. That was Bergeron’s second NHL concussion coming 14 months after his famous severe concussion that cost him the rest of the 2007-08 season after a hit from behind into the boards by Philadelphia’s Randy Jones.

“From my layman’s observations, he was lucid at the end, I was talking to him. He was disappointed because he had been through that stuff,” said Chiarelli. “Now take from that what you will. These things, especially when there’s multiple concussions … he came back very well from the Seidenberg hit. So his ability to recover right now shows that it’s been good. But who knows?”

Bergeron and the Bruins now have to adhere to the NHL concussion protocol. A player had to be symptom-free for a certain length of time and then has to undergo an exertion test and another SCAT to get cleared for activity.

Chiarelli said he doubts the league will implement any discipline on Giroux, who was not penalized on the play.

“I thought it was a shade late, but it’s in that area where when it’s at full speed, it’s tough to tell,” said the GM. “I did have a brief discussion with the league on it. It was a tough one to gauge at that speed, and especially at this level of competition. So I’ll leave it at that.”