A real estate firm working for the Virginia Baseball Stadium Authority has approached the owners of three potential sites for a stadium in Northern Virginia, offering to buy controlling interest in the properties, according to those close to the talks.

In two cases, the initial offers by Dallas-based Lincoln Property Co. were rejected; in the third case, conversations are in the early stages, the sources said. Lincoln Property, a national realty firm acting on behalf of the authority, a state agency established to bring baseball to the commonwealth, has contacted the owners of three of the five locations in Northern Virginia previously identified as possible stadium sites.

In one case, Lincoln proposed to buy the four 12-story co-op apartment buildings at the River Place complex in Rosslyn for about $60 million apiece. The cooperative's board of directors has discussed the offer but has not presented it to shareholders.

Lincoln also contacted the Morris & Gwendolyn Cafritz Foundation last month to make an offer on a tract in Pentagon City but was rejected, lawyers for the foundation said. The owners of a third site, near Dulles International Airport, described Lincoln's offer as "low-ball" and said they would not entertain it.

The contacts come as officials from the District, Virginia and Portland, Ore., wait to see where Major League Baseball may relocate the Montreal Expos. In Phoenix last month, representatives of the three jurisdictions presented preliminary stadium plans and finance packages to baseball authorities, who said they hope to make a decision in July.

It is not uncommon for localities or authorities seeking sports franchises to be in touch with property owners, even before they have a team, according to several national sports consultants. Even when attempts to land a team are in the early stages, getting an idea of how much land will cost helps establish overall stadium expenses, experts said.

District baseball officials have made no such overtures to property owners.

Real estate specialists also said that using a third party, such as Lincoln, to make offers is a standard practice for assessing a local real estate market.

"It can be a way of putting yourself in position, so that if you are picked you're further down the road and ready to go," said David M. Carter, a Los Angeles-based sports consultant.

"There's a lot of greasing of the skids that needs to go on in many of these cases, and if you wait you can find yourself behind in trying to acquire your sites," he said.

Officials at Costco, which owns a potential stadium site near Pentagon City in Arlington, said they had not received an offer from Lincoln to purchase their 16 acres. They said they have no intention of selling their land, which is home to one of the retail chain's most profitable stores.

The authority is expected to wait until the war in Iraq winds down before making any overtures to the Army, which owns the fifth Northern Virginia site at the Fort Belvoir Proving Ground, located just off Interstate 95 in Springfield.

None of the letters to property owners names the stadium authority, but officials from HKS, the architectural firm that has done drawings of stadiums at the five sites, said that Lincoln is working on behalf of their firm and the authority.

Brian Hannigan, a spokesman for the authority, would not comment on any potential real estate acquisitions, but said that Lincoln was working in an "advisory capacity" with Virginia baseball officials.

Other authority officials also would not comment, but they hastened to dispel any notion that the authority is speculating in land.

"Nobody is going to . . . consider getting the land until we get an actual award because now you're spending millions and millions of dollars," said Gabe Paul, executive director of the stadium authority. "I certainly wouldn't recommend anyone do that on speculation. . . . We're not land speculators."

Virginia hopes to build a 42,000-seat baseball stadium with about 25,000 square feet of retail and entertainment space. The authority has estimated the cost of such a facility at $400 million, of which $285 million would be financed through taxpayer money. However, according to authority documents, if the cost of land escalates, the cost of the stadium could go as high as $610 million.

In the case of the River Place site, there are many potential complications to a deal, according to officers of the co-op and officials of Westfield Realty, which owns the land where the buildings stand.

The buildings, which together contain nearly 1,700 units, are owned by several hundred shareholders, who would have to approve any sale by a 75 percent majority.

Westfield officials said they had received no offer for the land.

"It's definitely too early to tell what any potential outcome will be," said Steve Pappas, president of the River Place South board of directors.

On the Cafritz site, KSI Industries, a Vienna-based builder, wants to build a mixed-use complex and has already submitted plans to Arlington County. Much of the Dulles site, adjacent to Virginia's Center for Innovative Technology, belongs to KJS Properties, a Virginia-based company owned by Samir Kawar, a businessman, member of parliament and former transportation minister in Jordan. Another portion is a large tract of land owned by the Gudelsky family, which operates Loudoun Quarries.

Lincoln "submitted a low-ball letter of intent that was rejected," said Earl Glock, an attorney for Kawar. "We said it wouldn't fly and they have asked for a counteroffer and that is where it stands."

At the Fort Belvoir site, the authority will likely work with Sen. John W. Warner (R-Va.), who is chairman of the Senate Armed Services Committee and a strong proponent of bringing a major league team to Northern Virginia.

If Virginia wins the right to have a team, the state can exercise its power of eminent domain to acquire property on behalf of the authority, consultants and local real estate developers said. Arlington officials said they will not invoke their condemnation powers on their own.

Staff writers Michael Laris and Mark Asher contributed to this report.

A Dallas company has offered to pay about $60 million for each of the four 12-story co-op apartment buildings at River Place in Rosslyn.