But both teams say they are still working with their home cities to get a new stadium built.
When KTVU first contacted Oakland Mayor Libby Schaaf Thursday night, she said she did not know about this latest development and needed to speak with the Raiders first.
"Mark Badain, the CEO and President of the Raiders, spoke with me tonight and reiterated that the Raiders first priority is to stay in Oakland and obviously they have to explore other options. They have done that before. I'm sure they will do it again," said Mayor Schaaf.
The Raiders and the Chargers are rivals on the field, but off the field, they are joining forces with a plan to build a $1.7 billion NFL stadium in Carson to share.
The teams have hired an architect and came up with these artist renderings of what their shared stadium might look like.
"This did not come as a surprise. The Raiders are in negotiating mode. They have explored other options in the past," said Schaaf.
At Ricky's Sports Bar it was déjà vu. Fans say they are concerned their beloved team may move south again. The Raiders left for Los Angeles in the 1980's and stayed there for 12 years. As recently as last year, team owner Mark Davis visited San Antonio, Texas - fueling talk of a move there.
"We're the biggest Raider fans. We love our Raiders. We've been losing for the last decade but I hope we have enough say so that we can keep them here," said Jose Millan, a Raider fan. The Raiders and the Chargers issued a joint statement which says in part," If we cannot find a permanent solution in our home markets, we have no alternative but to preserve other options to guarantee the future economic viability of our franchises."
"It's negotiations and that's exactly what it is. You have to be able to negotiate and local people have to get it done," said Ricky Ricardo, owner of Ricky's Sports bar, a popular spot for Raider fans. The Raiders have been unable to get a new stadium built in Oakland. But Mayor Schaaf, even with her short time in office, says there's been progress in getting a deal done at the Coliseum site. She says the county and a new development company are now on board.