It is common (and often required by federal law) to offer a historic bridge slated for demolition to a third party. This however is not a preservation committment, and if nobody steps forward to take the bridge (which is the most common scenario) than the bridge would face demolition. I have however learned that Section 106 has not yet been conducted for this bridge, so VDOT is premature in describing this as a replacement project, before they have considered alternatives to avoid adverse effect.
It looks like they are considering relocating the historic bridge if a party comes forward to take it.