OAKLAND — The A’s and Raiders will soon get to compete against each other for a chance to redevelop their sprawling East Oakland home.

In a move intended to placate both teams, but which could pit them against each other, Mayor Libby Schaaf is proposing to allow the A’s and Raiders to make their own proposals for a development project that could include at least one new stadium and a mix of homes and businesses on the 120-acre Coliseum complex.

Schaaf’s plan also would extend the city’s exclusive negotiating agreement with its hand-picked development team headed by Floyd Kephart. The San Diego-based businessman has been working on financing a new football stadium as part of Oakland’s proposed Coliseum City project. But the 90-day extension, expected to receive City Council backing on Tuesday, would come with a condition that the two teams are free to offer competing plans.

Schaaf also is asking officials in Alameda County, which co-owns the Coliseum site, to sign on to the agreement.

“I’m trying to bring the city and the county together so that we proceed with a development strategy as joint owners because that is the only way that we will succeed,” she said.

Alameda County Supervisor Nate Miley said he now supported joining forces with the city and was “optimistic” that the Board of Supervisors would sign off on Schaaf’s plan at its Jan. 27 meeting.

Schaaf’s approach marks a shift in Oakland’s bid to keep its sports teams. For the past three years, the city has handed over exclusive rights to the Coliseum City project to a revolving door of development groups. Although they included heavy hitters such as Forest City and Colony Capital, the groups failed to finance the multibillion-dollar project or get buy-in from the teams. Meanwhile the Golden State Warriors proceeded with their plan to move to San Francisco and county officials felt spurned.

Schaaf’s plan puts local leaders in a better position to seek a grand compromise in which the A’s and Raiders agree to share the site, but it also carries risk, said Robert Boland, an associate professor of sports management at New York University.

“This also gives each club the opportunity to undercut the other or compete; and (for) one team to walk away angry if they aren’t getting what they are looking for in the negotiations,” he wrote in an email.

The new approach comes several days after a meeting with the Raiders and NFL executives during which the Raiders expressed an interest in finding their own development partner to make a proposal on the Coliseum site, sources said. The team did not respond to requests for comment on Saturday.

A’s co-owner Lew Wolff, a developer by trade, said he supported Schaaf’s approach. Wolff said the A’s would resume evaluating the feasibility of developing a ballpark project on the Coliseum site after having paused to see whether the city would continue exclusive negotiations with its hand-picked development team.

Kephart, whose exclusive negotiating rights with the city were to expire Wednesday, could not be reached for comment Saturday, nor could county leaders.

The A’s and Raiders are the only major league baseball and football teams that still share a home field. Their cohabitation has often been a chilly one with the Raiders frustrated by the A’s control of stadium concessions, and the A’s unhappy with the renovations to O.Co Coliseum that brought the Raiders back from Los Angeles.

Schaaf said she was still optimistic about being able to accommodate both teams, but acknowledged that it would be a challenge. Building both a ballpark and football stadium would mean less room for more profitable forms of development, such as homes or shops that could help offset the cost of stadium construction.

Schaaf has said previously that she is opposed to public subsidies for building stadiums but would be open to funding infrastructure improvements at the site.

“I am looking for ways to protect the public dollar, maintain my sports teams and create more economic vitality on that site,” she said.

Andy Dolich, a former executive with the A’s and the NBA’s Memphis Grizzlies, praised Schaaf for moving to finally get on the same page as county leaders and bring the teams to the table.

“This could very well be a circumstance where the mayor understands the clock is ticking,” he said. “You can’t wait forever. You’re going to have to push people in a way that they don’t want to be pushed to see what is reality and what is fantasy.”

Contact Matthew Artz at 510-208-6435.