Star players in the NHL don't usually get traded, but every so often a team is so desperate for a change that they trade their star player for a package of prospects and picks. Most of these trades are never seen coming and are remembered for a long time. Sometimes not even for the star player, but for the picks or prospects involved, usually for a silly reason. Toronto and Boston fans, I'm talking to you.
There are plenty of teams that, before the season started were slated to contend for the playoffs but have gotten off to a slow start and are in the mood to shake things up. That could mean that some players you would never think that could be traded will be traded. Does that mean they're available? No, but teams will be asking, and a general manager in a bad position would not be doing his job if he didn't listen to offers.