The team re-evaluated Bergeron's status for the game against Tampa Bay on Thursday night following the pregame skate, in which the alternate captain took part.
Bruins coach Claude Julien said Bergeron is "feeling pretty good." Bergeron had been sidelined since getting injured in the finale of the second-round series against Philadelphia when he was hit by Claude Giroux.
Bergeron had two goals and 10 assists in 11 playoff games this season before getting hurt.
"He brings a lot to the table, offensively and defensively," Boston captain Zdeno Chara said.
Also, Lightning defenseman Pavel Kubina was scratched for Game 3. Kubina, out since the first game of the conference semifinals against Washington, when his head went into the glass on a hit, has not resumed practicing.