BOSTON — How much longer can Zdeno Chara keep this up?

The Boston Bruins defenseman — and leader in ice time — will turn 42 this season, and sooner or later the window will close on his opportunity to skate around the ice again with the Stanley Cup. For his teammates, that means focusing on this season as their best and possibly last chance to win with him.

“The older you get, it’s just about winning,” said David Krejci, one of five holdovers from the franchise’s last title, in 2011. “We know that we’re not going to be playing in the league for 10 more years, but we have maybe three, four, five years left, who knows, but this is it. We worked really, really hard this summer to get the job done this year.”

Chara was already an eight-year veteran and two-time All-Star when he signed with Boston a dozen years ago, and the Bruins built a contender around him that went to the Stanley Cup finals twice in three years. (They lost to Chicago in 2013.)

Patrice Bergeron, Tuukka Rask, Brad Marchand and David Krejci are the only other players remaining from the 2011 champs. Bergeron is 33, Rask and Krejci will turn 32 during the playoffs, and Marchand will turn 31. (Steven Kampfer was traded away in 2012 and rejoined the Bruins this summer; he just turned 30.)