And a third possibility, the price set/asked is based on an expected release of a lien paid, the lien holder may have up to 90 days to release, or it's a negotiated release on a second being paid. Not really a short sale per se, might have been accrued interest on a NPN that was dropped is paid.
Forth, any lien holder, a materials or labor lien from a past project to be paid or arranged to be paid.
Fifth possibility, some liens are forgiven by municipalities, partially paid, sewer liens, lawn cutting or clean ups can be negotiated and released.
Last that pops to mind, they could be talking about an IRS lien or state tax lien. These are often released to allow a sale with the tax payer still owing taxes. More likely than 3,4 &5.
And it sure sounds like a short sale too, LOL. :)