Bergeron spent the night at Massachusetts General Hospital and underwent extensive testing, Bruins general manager Peter Chiarelli said in a statement. Bergeron was placed on injured reserve, meaning he is out of action for a minimum of one week.
"When examined this morning, his condition had improved greatly over last night, and he was released from the hospital," the statement said. "There is no timetable for his return to the ice."
Bergeron was injured in Saturday's game against the Carolina Hurricanes.
Bergeron collided near center ice with Carolina's Dennis Seidenberg and went to the ice, face-first. He remained down for several minutes while he was cared for by doctors and looked wobbly when he got to his skates and was helped to the locker room.
"He got dinged pretty good," said Bruins coach Claude Julien, who spoke to Bergeron after the second period. "He was speaking to me and then I took off and coached the third period."
Bergeron's 2007-08 season ended after 10 games following a hit from behind into the boards by Philadelphia's Randy Jones. He was close to returning during the playoffs, but the Bruins were eliminated in seven games in the first round by the Montreal Canadiens.
Bergeron returned for training camp and played in 30 of Boston's first 31 games. But he had yet to regain his scoring touch, totaling four goals -- one in his last 19 games.
His teammates went to St. Louis to play the Blues on Sunday night, but their thoughts were with Bergeron.
"We know what's at stake and our prayers are with him, that's for sure," goalie Manny Fernandez said Saturday. "We hate to see a guy like that go down again."