As Frank said, short sales can take many months. And once they are closed, the new owner can give you a new lease( once yours expires) or if the buyer is going to move in, you have UP to 90 days. I cant stress it enough, if you have a lease that is in writing by both parties, thats the only way it helps you. If not, they can give you a 3 day notice to quit.
I dont know if you have open communication with the owner or property management company, if so, I would think they would let you know about the final sale date of the home and if it is an investor or owner occupied.
A releif for you or not is that a short sale is everything but short, and when they finally get an approval it will take about 30 days to close. Considering you have a lease, your lease goes with the house, and the buyer buys it. The buyer buys your tenancy, and has to honor the contract, you signed it to protect you and the landlord. If you are on a month to month, they can give you a 30 day notice.
Timeline wise, The fastest short sale approval I obtained took 3 weeks, the longest 5 months.
There are a million variations, but these are the basics.