The home will go to auction prior to being listed as a foreclosure. If there are no outside bidders the bank will then take the home back. This process takes time.
The owners can still become current on this home by working out a payment with the bank. If the home does go on the market it may be listed as a Short Sale property first. Some people are choosing to not Short Sale their homes and deciding to stay in their homes until the foreclosure process is complete as this takes many months.
If you are interested in looking at foreclosures or Short Sales in the Downers Grove area I suggest you work with an agent that is verse in both.