An offer by Cablevision that made the Jets appear to be low-balling on air rights over the Hudson rail yards called into question yesterday the MTA’s priorities in the sale. At the same time, a source close to the proposal for a West Side stadium told The New York Sun a coalition will issue a report today showing that Cablevision’s offer of $600 million has a present value of as little as $60 million.

On Friday, Madison Square Garden presented to the chairman of the Metropolitan Transportation Authority, Peter Kalikow, a proposal under which the Garden would purchase air rights to the West Side rail yards for $600 million for mixed-use development centered on residential construction. The Jets’ offer for air rights was $100 million.

Cablevision and the Garden have long opposed Mayor Bloomberg’s plan for a New York Sports and Convention Center, a domed stadium that would serve as the home field for the Jets football team and principal venue for the 2012 Olympics, should New York be designated host city. The company’s bid appeared to undermine the stance maintained by the mayor and other proponents of the plan that the Jets were the only party interested in purchasing rights to build over the rail yards, a position often cited in response to opponents’ complaints that there has been no competitive bidding for the rights.

The mayor and the Jets organization were dismissive of Cablevision’s proposal. In a written statement, a spokeswoman for the Jets, Marissa Shorenstein, called the offer a “P.R. gimmick” meant to help Madison Square Garden retain its “monopoly” on sports facilities in Manhattan.

Furthermore, a coalition of the plan’s supporters was to release a report today demonstrating that, in present-value dollars, the Jets’ offer is more generous than Cablevision’s.

According to the source, who declined to be identified by name, the report says the Jets’ $100 million offer is in present-day lump-sum terms, and over the course of a typical 49-year lease the aggregate amount paid to the MTA would have a value of $378 million in 2005 dollars.

Cablevision, the report is said to have found, will only pay out an aggregate amount of as little as $250 million to the MTA, once the cost of putting a deck over the yards is deducted, which in present-day lump-sum terms is worth only $60 million.

Criticisms of Cablevision’s offer aside, opponents of the stadium plan who have called for the MTA site to be opened up to competitive bidding said the MTA has an obligation to take the Garden’s offer seriously.

Assemblyman Richard Brodsky, a Democrat of Westchester County, said he thought the MTA would be under legal obligation to consider seriously the Garden’s proposal. Mr. Brodsky, who is chairman of an Assembly committee that conducted a hearing Thursday into the city’s deal with the Jets, said the MTA board’s top priority in selling the air rights should be the financial well-being of the MTA, not in subsidizing the Olympic stadium the city administration craves.

“The MTA is not a stadium-building entity – it’s a transportation entity,” Mr. Brodsky said.

The executive director of the Hudson Yards Coalition, James Whelan, said, however, that the MTA should consider not only the amount offered for the rail-yard site, but also what bidders proposed to put atop it.

Mr. Whelan, whose coalition is a collection of labor, business, development, and civic organizations, said the city and the MTA should consider that the Jets stadium is “part of a comprehensive plan that addresses several needs: the need for residential space, the need for commercial space, and the need for convention facilities – and that it’s putting in place the critical component to bringing in the 2012 Olympic Games to New York City.”

A spokesman for the MTA, Thomas Kelly, said: “We’ve received the bid, and we’re reviewing it.” He said the MTA was “just interested in selling the property” and would not comment at this point on how the site should be used.

“We will do what’s in the best interests of the MTA and its commuters,” Mr. Kelly said.

The sale of the air rights for the rail yards is part of an MTA plan to make up for a $586 million projected shortfall in fiscal year 2006 by selling some of its assets.