It’s for real: Mayor Vincent C. Gray (D) and D.C. Council member Jack Evans (D-Ward 2) have their eyes on possibly putting a Washington Redskins headquarters and training facility on city-controlled land just south of RFK Stadium.

The debate in the future weeks, months and perhaps years falls along these lines: Is using the land for a Redskins facility a waste of one of the city’s largest and most desirable parcels? Or is a Redskins facility one way of catalyzing development in an area that has seen big plans drawn up but not the wherewithal to turn them into reality?

One developer, who is part of a group that is bidding on a plan to develop a portion of the Hill East parcel, said he was not opposed to the notion of a Redskins facility. “The training idea is not necessarily mutually exclusive from the master plan redevelopment that we proposed,” said Calvin Gladney of Mosaic Urban Partners.

But just how much redevelopment will the city need to forgo to lure the Redskins?

The magic number appears to be 33 acres, which is roughly the size of the state-of-the-art Tampa Bay Buccaneers facility that Gray and Evans quietly visited in the fall — a facility that Redskins General Manager Bruce Allen helped build when he was in the Bucs’ employ.

The Hill East plot is 67 acres; subtract roads, parkland and other features, you have 50 acres of developable land. By that math alone, a Redskins facility extensive enough to capture the team’s interest would replace half of the development.

To get more than 30 acres on the northern end of the Hill East tract, the plot would have to extend as far south as the northern edge of the D.C. jail. That leaves a triangle of land that is, thanks to its proximity to the jail and its non-proximity to the Stadium-Armory Metro station, the least desirable part of the tract.

If the Redskins parcel extended only as far south as C Street SE but went east to the Anacostia shoreline, the plot would be just shy of the magic 33 acres. That, however, would encroach on the southern tip of the RFK parking lots.

Bill Hall, who chairs the board overseeing the stadium, said Thursday that the RFK campus would be an “ideal location” for a Redskins compound. But the governing body, Events DC, has not been part of the most recent discussions, Hall said.

There are a few reasons why Gray and Evans might not be talking about the RFK lots right now. The 1988 RFK use agreement says the land can be used only for “recreational facilities, open space, or public outdoor recreation opportunities . . . [or] other similar public purposes.” Whether a pro football training facility fits into those strictures is unclear, although Hall said there is “no question” that it would be allowable.

So why not put the Redskins facility entirely on the RFK parking lots, where tax-generating development is prohibited?

There’s a big catch for a wholesale takeover of the RFK lots: If the city has any hope of having the Redskins stadium follow a training facility back into town, conventional wisdom holds that maintaining every last RFK parking space is crucial.

Many await what Gray will present to the community this month, but from what is known thus far, it’s hard to visualize a Redskins training facility that will be big enough to meet the team’s desires, generate significant economic development and allow city fathers to indulge their hopes and dreams of a new Redskins stadium.

Staff writer Jonathan O’Connell contributed to this report.