New York City will have to abandon its bid for the 2012 Olympics if a deal on the West Side Stadium for the Jets is not brokered soon, Mayor Bloomberg said yesterday.

“If we were not to get the stadium going very soon, we will have to drop out of the competition for the Olympics,” Mr. Bloomberg told reporters before the Jets season-opener at the team’s existing stadium in East Rutherford, N.J.

The stadium, which would cost $1.4 billion, is the centerpiece of the Bloomberg administration’s Olympic bid plan. It is also the anchor for its larger West Side redevelopment project, which includes the expansion of the adjacent Jacob Javits Convention Center.

The plan calls for the Jets to pay $800 million and for the city and state to pitch in $600 million to build a retractable roof and a platform over the Hudson Rail Yards on which the stadium would be built.

After joking about whether the mayor could join the team as a quarterback, Mr. Bloomberg and Jets owner Woody Johnson again said the stadium was an investment that would lure in conventions and sports events year-round, create jobs, and pump money into the city’s economy.

Critics have blasted the project, saying it will increase traffic and congestion on the West Side, exacerbate air pollution, and undermine the city’s 2012 Olympic bid. They have also vowed to sue to block construction.

Further angering opponents is the mayor’s plan to circumvent the City Council, the state Legislature, and the City Planning Commission.

Assemblyman Richard Gottfried, a Manhattan Democrat and an ardent opponent, said the city has failed to provide any evidence the stadium needs to be built in that location in order to clinch the bid.

“He is trying to use the Olympics to pressure people to agree to the stadium at that site and he is trying to use the supposed International Olympic Committee schedule to argue for making the decision right now,” Mr. Gottfried said in a phone interview. “Both of those things are false.”

New York is one of five finalists for the 2012 Olympics along with Paris, London, Madrid, and Moscow. The IOC will announce the winning city in July,

Mr. Bloomberg said he was optimistic about finalizing the stadium deal, but that he “had to be able to look the IOC in the eye and say this stadium is going to be built.”

“When people stop and think about what it means for New York City to have a stadium they’ll come around,” he said.