A 12-acre lot just north of Riverdale Park Station on Baltimore Avenue could soon be developed.

The Washington Metropolitan Transit Authority, which has owned the 12-acre lot south of Albion Road since 1989, announced that it would be putting it up for sale as a surplus property this week.

The lot is currently zoned for single-family homes, similar to the Calvert Hills neighborhood to its north, but a neighborhood association wrote to College Park leaders in December expressing concerns that it might be rezoned.

“There is a significant risk that a purchaser would seek a rezoning to allow for denser development,” the Calvert Hills Civic Association wrote.

That’s almost certainly true. No infill developer wants to go through all the work of regrading a hilly site, getting the proper permits and contracting out the construction work just to build a dozen single-family homes.

On the other hand, the area already lost a lot of natural green space when Riverdale Park Station was developed, and the lot provides a nice break between the “surban” townhomes and restaurants and the older traditional neighborhood to their north.

(There’s an environmental argument on the other side too, as properly done infill projects can help reduce sprawl, boost transit ridership and spur more walkable neighborhoods.)

But if neighbors want to stop the land from being developed, they’ll need to act fast and dramatically. Since WMATA and the county are key players, the only way to stop it may be, as the civic association suggested, for the city to buy the land itself (at a cost of more than $2 million) or to find some long-shot basis for a lawsuit.

Either strategy is both expensive and faces steep odds, which makes it most likely that the area will be getting some more townhomes.