The son of Washington Redskins owner Jack Kent Cooke has met privately with a Loudoun County developer about the possibility of building a football stadium in eastern Loudoun County near Dulles International Airport, according to sources familiar with the negotiations.

Also involved in Cooke's discussions with developer Robert DeLuca was Loudoun County Supervisor Steven W. Stockman (I-Broad Run), sources said.

Stockman confirmed yesterday that confidential talks about a new stadium in the county are under way but said they are at a "very, very delicate" stage and declined further comment.

"I would just say in the roughest, vaguest terms that the whole metropolitan area is up for grabs and business people need to have some confidentiality in major undertakings," he said. "If you talk about something prematurely, you can wreck everything, and I just don't want any press at all."

Details such as precise locations and financing options under discussion could not be learned yesterday.

Cooke confirmed yesterday that his son, John Kent Cooke, the vice president of the Redskins, held a "private, confidential meeting" with DeLuca but declined to comment on the substance of the talks. "Neither I nor they will talk about it," he said.

The elder Cooke is seeking a new arena to replace 55,000-seat Robert F. Kennedy Stadium, which he says is too small. He has said he would like a 75,000-seat domed stadium and has threatened to move his team to the suburbs if his demands are not met.

Until now, that threat had been considered little more than a bargaining ploy. Cooke has said repeatedly that the District remains his first choice for a new stadium. Earlier this week, several officials from the suburbs -- Loudoun was not among them -- pledged their support for the District's efforts to keep the Redskins in the city.

"I wouldn't say the city is upset," said a spokesman for Mayor Marion Barry. "It doesn't seem to be a serious proposal."

Loudoun generally has not been considered a serious contender in the stadium sweepstakes. Situated west of Fairfax County, the largely rural, but rapidly developing, county is about 20 miles from the center of the District at its nearest point and is served primarily by a network of narrow two-lane roads.

"Even if it were used only on Sunday, the road network could not properly serve that type of facility," said Philip A. Bolen, the Loudoun County administrator. However, he added, "If there were a business conglomerate that could put together a concept that could work, I'm sure they would be given an opportunity to express it."

DeLuca, who owns the Countryside shopping center and office complex on Rte. 7 in Loudoun County, is a proprietor of J&B Corp., a development firm that also is involved in low-income housing rehabilitation for the D.C. Department of Housing and Community Development. He could not be reached for comment yesterday.

Jim DeFrancia, the developer of the Countryside project, said he was aware of the discussions involving the stadium, but said he was unsure of where DeLuca could build such a large facility. "I'm at a loss to understand where he might get the land," said DeFrancia, president of Weston Capital Co.

DeFrancia said DeLuca is "not a landowner," adding, "I was a little mystified" about his involvement with the Cookes.

Stockman, a lawyer whose office is located in the Countryside development, said, "All I would say is there's a lot of land in Loudoun County {and} if someone wants to buy land, there's land for sale."

DeFrancia said he has heard "street talk" suggesting that other Loudoun County businessmen might be involved in the discussions with the Cookes. "What I understand is that there is a segment of the Loudoun business and development community that would very much like to see a stadium out here," he said.

Development experts said yesterday that any such project would almost certainly have to be built in the area just north of Dulles International Airport in eastern Loudoun, where most of the county's 8,000 acres of industrially zoned real estate is situated.

"There are just huge amounts of land out there," one expert said. "It's in the flight path of the airport, so it's really not suited for residential development."

The area also is served by Rte. 7 and by Rte. 28, which is slated for widening to an eight-lane freeway.

Considerable secrecy seems to have surrounded the Cookes' foray into Loudoun County. Stockman told a reporter, "If you get hold of anyone and anyone comments, I'm going to sue them."

County board Chairman Betty W. Tatum said yesterday that she was unaware of the discussions but added, "I'm sure we'd be willing to talk."

A spokesman for the D.C. Department of Housing and Community Development described DeLuca as a "quality" developer who recently renovated a 36-unit rental building at 2630 Adams Mill Rd. NW. J&B Corp. agreed to set aside part the building for low-income housing after receiving a $2 million low-interest loan from the city, the spokesman said.