IS THERE A NEW SHADOW INVENTORY COMING?

The shadow inventory (homes in delinquency or foreclosure that will eventually come on the market) keeps shrinking.  But, TRULIA Chief Economist Jed Kolko says that census data just released shows that more shadow inventory may be looming.  2013 2Q vacancy survey shows that 5.6% of all housing units are vacant.  

Are the owners waiting til prices have gone high enough to unload them?  If they come on the market now… how will the market be affected?  Right now, inventory is low so they MIGHT get a quick sale and get rid of the expenses of carrying the property.