There's going to be a lot of good defensemen exposed to the draft that teams will lose for "nothing"
I'm bored at work so I looked through some teams made a potential defense for an expansion team (w/o Oilers), though its a bit hard to project how contracts will turn out.
Anaheim - protect Bieksa (NMC), Fowler, Lindholm; expose Vatanen, Despres, +
Arizona - protect OEL and Pronger (jk)
Boston - protect Chara, Krug, +1; could expose Colin Miller, Seidenberg, McQuaid, Morrow
Detroit - protect Ericsson, Green, Kronwall, expose B. Smith
Minnesota - protect Suter, Brodin, Scandella, expose Spurgeon
LA - protect Doughty, Muzzin, Martinez, expose
Rangers - protect Girardi (nmc), Staal (nmc), McDonough; expose Klein
Ottawa - protect Phaneuf (nmc), Karlsson, Ceci/Methot; expose Methot/Ceci
Nashville - protect Weber, Josi; expose one of Ellis or Ekholm
Ekholm - Spurgeon
Seidenbeg - B. Smith
Klein - Methot
Nashville is where I gave up, my thoughts are that if you're going to expose a good dman you should make sure it's an expensive one or one on an expiring contract. Or tempt the expansion team with a forward.