Patrice Bergeron and Zdeno Chara signed contracts that will keep them in Boston for a long time. It will be completely up to them if they ever want to leave as well.
According to The Boston Globe, Bergeron's three-year extension and Chara's seven-year extension include no-movement clauses.
The clause has become a bit of a custom for Bruins signing long-term deals. Tim Thomas and Marc Savard, despite their names popping up in trade rumors over the past year, also have such terms.
The clause requires that a team gets consent from the player in order to make any trade. The difference between a no-movement clause and a no-trade clause is that a no-movement clause prevents teams from waiving or demoting a player.