If done properly, the foreclosure will remove your lease and right to buy the home.  Depending upon how the homeowner rebuys or redeems the home, i.e. in his name or another's, you may be able to salvage your right to buy.  You should record your lease with your right to buy at the register of deeds office.  If possible, you should enter into a new agreement with whoever ends up with it.  Obviously if he is buying it for lease your purchase price should be less.  Contact me if you would like to discuss in more detail at johntatone.com.