According to David Garrick of the San Diego Union-Tribune, Chargers special counsel Mark Fabiani said on The Mighty 1090 AM radio show that the team will make the request in January.
"If everything is moving ahead, obviously we're not going to be standing on the sidelines and watching everything go by," Fabiani said. "We've got to stay in the game to protect the franchise."
Fabiani claims the expectation is the St. Louis Rams and Oakland Raiders also plan to file for relocation to Los Angeles, with the Chargers unable to afford losing "the roughly 25 percent of their season ticket holders that live in Los Angeles and Orange counties."
The Chargers have been trying to get a new stadium, whether in San Diego or Los Angeles.
Derek Togerson and Artie Ojeda of NBC San Diego noted the San Diego Stadium Coalition recently developed a plan in an effort to get a new home for the Chargers built that would require the team to put up "more than $700 million" for a stadium to be built as part of a convention center expansion.
Per Garrick's report, the vote for the convention center expansion would take place in June 2016, and Fabiani said NFL owners are expected to vote on a Los Angeles team in late January.
Former Citizens Stadium Advisory Group spokesman Tony Manolatos is quoted in Garrick's report as saying the Chargers "have to take this step on applying for relocation if they want to try and maintain what little leverage they have left" because he believes recent efforts have helped San Diego's case to keep the franchise.
There is currently a stadium proposal in Los Angeles that has yet to break ground, though the Los Angeles Times recently published photos of what developers are expecting it to look like if and when it gets approved.
The NFL hasn't had a team in Los Angeles since the Raiders and Rams moved out following the 1994 season. Getting a team back to one of the United States' biggest media markets has been a hot topic for years, though the Chargers' plan to file for relocation may be the most substantive move to make it a reality.