While Bruins general manager Peter Chiarelli held a press conference to discuss yesterday’s trade deadline, he also delivered the most pertinent news with regard to his team’s immediate future.

And it wasn’t good.

Chiarelli announced that center Patrice Bergeron suffered a concussion — the fourth of his career — in the second period of the B’s 3-2 victory against the Ottawa Senators on Tuesday at the Garden.

Chiarelli described the concussion as “moderate” but warned that brain injuries are hard to gauge. He gave no timetable for a Bergeron return.

“I talked to him about an hour ago and he was in very good spirits. He was out walking,” Chiarelli said at his 5 p.m. press conference. “He was annoyed at it, and he was emotional (Tuesday) night. I asked him if I could update the media and he said, ‘Sure.’ . . . He sounded really good and I told him that we’ll work together in getting him back.”

Bergeron was injured while defending against Ottawa’s Colin Greening, who inadvertently caught him in the back of the head behind the left ear with his elbow. Bergeron got up slowly and skated off the ice. He did not return.

Chiarelli said the Bergeron injury had him thinking about obtaining more help up front, but he decided against it.

“It crossed my mind,” the GM said. “But we’ve got a good group. We added a terrific player (Tuesday in Jaromir Jagr). We added a useful player the other day in (Kaspars) Daugavins, we’re a well-coached team, we defend well, we’re going to improve our offense. You see a player like Patrice go down and there’s no way I’m going to replace him because there wasn’t that caliber of player, so I’m not going to go around chasing it all day.

“And you’ve seen it across the league where teams have picked it up when they’ve had injuries, and I expect us to do the same.”