The speaker of the City Council, Gifford Miller, tried to shift the debate on the development of the West Side yesterday, saying that all of the key players agree that the Hudson rail yards should be rezoned to include residential and retail space and that the Metropolitan Transportation Authority’s bidding process should begin anew with that understanding.

Mr. Miller, who is hoping to win the Democratic primary and run against Mayor Bloomberg in November’s election, said that until now, developers who were interested in the air rights to the 13 acres where the New York Jets have proposed erecting a football stadium have not been given assurances that they can build what they want.

As a result, he said, the process has favored the stadium, a project Mr. Bloomberg is pushing because it would offer convention space and could serve as an Olympic arena.

“We have currently two real bidders on this site, both of whom essentially require a substantial rezoning,” Mr. Miller said.

Mr. Miller and the other three Democrats running for mayor have been attacking Mr. Bloomberg on the stadium issue for months, saying the mayor is putting the football team ahead of schools and other important priorities.

The other Democratic candidates have also said the MTA should go back to the drawing board and start the bidding over.

Mr. Bloomberg has made the case that the stadium would serve as an economic engine for the now-blighted area and would increase revenue for the city so that it could more easily pay for its other services.

Mr. Miller said if the mayor supports the rezoning of the MTA’s rail-yards property, he should “make that clear to everyone who’s going to be bidding on this land.”

For several weeks, Mr. Bloomberg has been saying the city would work with any developer interested in building on the site. Yesterday, a spokeswoman for the mayor, Jennifer Falk, said: “The city will evaluate a specific rezoning proposal when it is received and in accordance with typical processes.”

Mr. Miller also seemed to indicate yesterday that he was against a crucial part of the Jets’ plan, which would allow for more apartments and commercial buildings in the area around the stadium.

The council and the mayor recently brokered an agreement to clear the way for new apartment towers and offices in the vicinity. Mr. Miller said stuffing 4 million additional square feet of building into the area would throw off the density levels.

Meanwhile, according to the Associated Press, a group of pro-stadium elected officials, including Reps. Gregory Meeks and Joseph Crowley, sent a letter yesterday to the MTA chairman, Peter Kalikow, urging him to go ahead with tomorrow’s scheduled board vote to choose among the bids received from the Jets, Madison Square Garden, and TransGas.

“There is a long and disturbing history in New York of people calling for a delay in the development process, or claiming that the process is tainted, simply to stop any development from moving forward,” the letter said. “As you know, we are hearing those calls again in an effort to block the New York Sports and Convention Center.”