"We believe that a downtown multi-use facility will attract broad support from throughout our entire community," the Chargers said Tuesday in a written statement.
The announcement generated a tepid response from two of San Diego's most powerful politicians.
"Most experts we've talked to have concluded that building a stadium downtown -- on land not owned by either the city or the Chargers -- would increase costs by hundreds of millions of dollars and take years longer to complete," San Diego Mayor
Last year, the city and county of San Diego proposed a $1.1-billion venue near the site in Mission Valley where the Chargers currently play at
The statement from Faulconer and Roberts said it's unclear how the Chargers will finance a downtown stadium and that two-thirds of voters must approve any ballot measure that increases taxes.
"This is an extremely high hurdle to clear," the statement said.
But the Chargers believe a downtown stadium coupled with an expanded convention center would create an "unparalleled entertainment and sports district" in an area that includes Petco Park and the Gaslamp Quarter.
"And we hope that ... those who have supported the Mission Valley site will keep an open mind and consider supporting what we believe is the best way to secure a permanent home for the Chargers in San Diego," the team's statement said.
The Chargers used the ballot initiative process last year to bypass lengthy and expensive environmental review for the stadium they wanted to build with the
The Chargers will collaborate on the effort with an existing citizen's coalition whose backers include former Padres owner John Moore's JMI Realty.
"Most neutral observers would say that downtown has an increased legal and financial risk," said Adam Day who served as chairman of the former stadium advisory group appointed by the mayor.
The Chargers announced last month that they would play the 2016 season in San Diego and seek a long-term stadium solution there.
If that doesn't work out, the Chargers have an agreement with the Rams to share the planned stadium in Inglewood.
The Chargers have until Jan. 15, 2017, to exercise a one-year option to move to Los Angeles. The option can be extended one year if voters approve public financing for a San Diego stadium.
MORE ON THE NFL: