Though the NHL season is still relatively young, it's nearing the time when changes are coming.
Some teams are just where they want to be; others realize that they need a change. That change may be, "Well, this isn't our year," which calls for rebuilding trades of sorts. Or, it might be, "We're missing that one player."
Under-performing teams will look to rid themselves of upcoming free agents or otherwise valuable assets. For teams needing a defenseman, these players are likely to be available.