In Va (where I am) a lease supersedes a sale. Sounds like LA is the same (based on previous response).
What does your landlord say? I have a property under contract now that was rented when we put it on the market. The tenants moved 9/30, and closing is supposed to be this Friday. It's fine. If you know that the property's for sale, and the landlord knows you know, it seems like you could have an open and frank discussion about his intentions vs. yours. But, I really wouldn't sweat it very much if you have read your lease, and if your state recognizes lease rights like VA does.
Why would your landlord buy you out when he doesn't know if he can sell the property yet, or how long it will take? Some buyers who might be looking for an investment property might like that there is a lease in place, especially if you are caring for the home and paying on time. If he sells to someone who likes the house, he'll have to try to buy you out then. Maybe you've heard about the market... that could be awhile. :-)