The contract is worth $52 million, which comes out to a yearly salary-cap hit of $6.5 million. It will keep him in Boston through the 2021-22 season.
Given how important Bergeron is to the Bruins, that's actually a pretty good cap hit for the team and probably less than he could have received had he made it to the open market next summer. He's one of the best all-around players in the NHL and is still only 27 years old.
Bergeron finished the 2012-13 regular season with 10 goals and 22 assists in 42 games and was a rock during the Bruins' run to the Stanley Cup Final.
He made headlines during that Final series when he played through Game 6 with a series of significant injuries, including a broken rib, torn cartilage, a separated shoulder and what was later revealed to be a small hole in his lung. He spent time in the hospital after that game ended.
When he's on the ice and in one piece, he's not going to put up huge scoring numbers and will usually average around 20 goals and 40 assists per 82 games played. But when you combine that producution and his skill with his shutdown defensive game and his ability to match up against other teams' top players on a nightly basis, he's one of the most valuable players on the team (if not the most valuable) and one of the best players at his position.