Ignoring for a moment the unlikely mortgage qualification of your borrower (most lenders have a time requirement of 2 years or more with a foreclosure or short sale) this question is best posed (and answered by) to a good Michigan Real Estate Attorney.
Any legal advice you may receive here is probably worth what you are paying for it...
Jim Ryan, HSOA 703 591 5626 ext 419
Beyond that, it's likely the original owner's credit was damaged by the short sale. So even if the original owner has the money to buy, it's unlikely that he/she would be able to qualify for the mortgage.
If you're thinking about doing this as an investor--buying a house, renting it back to the seller, then eventually selling it back--don't. There are way too many problems involved in that. You may think you're doing a good deed, but it'll come back to bite you.