The Raiders and Chargers have been going head to head in the AFC West for a long time, but Oakland owner Mark Davis said Friday that their budding partnership on a possible $1.7 billion stadium near Los Angeles is not hard to figure out.

“My dad helped Alex (Spanos) get in the league, and while we have been fierce rivals on the field, we have common philosophies and goals,” Davis said. “And we have the same need. We are the two California teams that need a stadium.

“Together, we may be able to get it done.”

Ideally, Davis said, continued efforts to build a new stadium in Oakland will pay off first.

“That’s our No. 1 priority, to stay in Oakland, always has been and will continue to be,” Davis said. “We’re really trying to stay, and now there’s a great opportunity in Los Angeles. We need to get something done.”

The Chargers and Raiders both issued statements Thursday night laying out the privately financed stadium in Carson (Los Angeles County) as a developing backup plan while they continue to pursue stadium deals in their current markets.

Oakland Mayor Libby Schaaf said Raiders team president and CEO Marc Badain called her Thursday night.

In a statement issued Friday, Schaaf said she had brought city and Alameda County officials together with the Raiders “to explore ways to privately fund a new home for them in Oakland.”

She reiterated her stance on “delivering a deal that works for the Raiders, the fans and the taxpayers. Oakland deserves nothing less.”

While there hasn’t been a lot of progress with the city of Oakland since Davis told The Chronicle it was “their last chance” a year ago, there has been some. An environmental impact report has been completed. The Raiders are just waiting for an official proposal on how they would split up the 120 acres with the A’s at the existing Coliseum site.

There doesn’t seem to be enough space for two stadiums, parking spaces and the retail shops that were a big part of the original “Coliseum City” plans.

Meanwhile, it has been reported that the Chargers-Raiders partnership was born in response to St. Louis Rams owner Stan Kroenke announcing plans in January to build a stadium in Inglewood (Los Angeles County). But league sources say that is not the case, that Chargers officials have been meeting with Carson officials for 10 months.

The Chargers brought the Raiders on board last month, and the teams partnered with investment firm Starwood Capital Group to purchase a 168-acre parcel near Interstate 405 in Carson. Manica Architecture, which is drawing up the plans for the joint stadium as well as the Warriors’ arena in San Francisco, said the projected capacity for the stadium is 72,000.

The site has been in play for a while. When the Houston Texans were granted an expansion team in 1999, they beat out a Los Angeles team that would have been based in Carson.

“It’s one of the sites that has always been of interest to the Raiders and the NFL,” Davis said.

Carson officials held a City Hall news conference/celebration on Friday morning, but there were no Raiders representatives present. Chargers special counsel Mark Fabiani attended but didn’t go on stage or speak.

Raiders and Chargers fans were on hand as politicians and labor leaders talked about the jobs that the teams would bring.

“It will change our city forever,” Carson Mayor Jim Dear told the crowd. “You are at the right place at the right time.”

“Carson2gether,” a group of business and labor leaders, intends to start a petition drive for a ballot initiative to get voter approval to build the stadium.

The Chargers and Raiders must still present the Carson proposal to the NFL relocation committee, and it would then require 24 yes votes from the 32 owners to green-light a move.

One league official said it’s “a race between three teams for one stadium and two spots in Los Angeles.”

The Chargers, Raiders and Rams can all terminate their leases at the end of the 2015 season and move to Los Angeles in 2016. (The Raiders have agreed to terms on a one-year lease extension at the Oakland Coliseum.)

The two teams that could move to Los Angeles in 2016 would need a temporary home for a couple of seasons, and league sources said that the recently-renovated Rose Bowl would be suitable.

Fabiani told ESPN why a football-only stadium in Carson is attractive.

“There’s a lot of space on the land, so you can do whatever you want to create a great fan experience on game day,” he said. “It’s easily accessible from L.A. and Orange County. It’s easily accessible from the freeway systems. There will be ample parking.”

And it would be the home of two teams.

“That was always, I think, a given,” Fabiani said. “If ever there was a stadium built, there were going to be two teams in it. That’s just the reality of the world. And two teams make it much easier to finance. That’s not brain surgery.”

The Los Angeles market has not had an NFL team since the Rams and Raiders departed for St. Louis and Oakland, respectively, in 1995.

Vic Tafur is a San Francisco Chronicle staff writer. E-mail: vtafur@sfchronicle.com Twitter: @VicTafur