Today is the deadline for bids for the Metropolitan Transportation Authority’s 30-acre property over the West Side rail yards, with competing proposals expected from the Jets and Cablevision.

The Jets have spent several years gathering support for a $1.7 billion stadium to serve as the football team’s new home, an extension for the Jacob K. Javits Convention Center, and the Olympic Stadium should New York win the right to host the 2012 Summer Olympic Games. Cablevision, which owns Madison Square Garden and considers the stadium competition for its convention business, is expected to submit a bid for a mixed-use residential development on the site.

An energy company, TransGas, could also make a bid. The $700 million offer for the rail yards it has extended has been seen as part of an effort to win the MTA’s approval for plans to build an electric power plant on the Williamsburg waterfront and for a 20-year contract for the authority to buy power from TransGas. But that bid has been largely dismissed by the MTA and the city.

Cablevision has offered $600 million for the rail yards and the Jets have offered $100 million, with Mayor Bloomberg and Governor Pataki pledging an additional $600 million in state and city funds to help construct the stadium. The Jets have said they would raise their bid to make it competitive with Cablevision’s.

In anticipation of today’s deadline, speculation was in high gear, with activists and politicians expecting a possible fourth bid from a foreign company without ties to local New York politics.

“I have heard of an Asian company that may make a bid because they don’t have to worry about upsetting Dan Doctoroff,” Assembly Member Richard Gottfried told The New York Sun. Large New York developers are widely considered to be sitting the bidding process out for fear of alienating Mayor Bloomberg and Mr. Doctoroff, the deputy mayor for economic development, who oversee zoning and development applications.

There were also reports that the Jets are discussing with Vornado and the Related Companies a sale of the air rights over the rail yard should their bid win, enabling the football team to increase its bid, and for the developers to transfer roughly 4 million square feet of development rights to the nearby Hudson Yards. To transfer the air rights, the Hudson Yards would have to be rezoned again after the City Council just approved a rezoning of the area for 24 million square feet of additional development.

A spokeswoman for the Jets, Marissa Shorenstein, had no comment.

In other stadium news, Mayor Bloomberg, the Jets stadium’s chief supporter, denied claims yesterday he had threatened Cablevision CEO James Dolan that the football stadium would be built “whether you like it or not,” as Mr. Dolan recounts the mayor said during a conversation at a Knicks game last spring.

Mr. Bloomberg said he “would never threaten anyone,” that it is “ridiculous,” and that he will comply with all of the laws and “fulfill obligations as the CEO of this city.”

As for whether the Jets bid will beat out a bid by Mr. Dolan’s Cablevision, “the Jets spent three years on their plan and Cablevision only spent three weeks on theirs,” Mr. Bloomberg said.

Mayor Giuliani appeared in an advertisement last night supporting the Jets stadium, known officially as the New York Sports and Convention Center. “The Sports and Convention Center goes to creating jobs. A city that continues to grow, that continues to build, is a city that can put teachers and firefighters and police officers – tens of thousands of New Yorkers – to work,” Mr. Giuliani said in the ad, which aired on WNBC-4 during an episode of “Law and Order.”