Now that the Oakland A’s have announced plans to build a new ballpark on the waterfront next to Jack London Square, the city should solicit proposals from all comers for the Coliseum site the team would be abandoning.

After a botched plan last year to build a new ballpark next to Laney College, A’s President Dave Kaval last week unveiled drawings for a new field of dreams at Howard Terminal.

The waterfront site, owned by the Port of Oakland, presents the A’s with significant obstacles, including transportation for about 34,000 fans, railroad tracks separating the site from downtown and multiple environmental issues.

The site also provides unique benefits: waterfront views, proximity to Jack London Square and downtown, and potential for accompanying residential development that could turn the neighborhood into a destination location.

So, if that’s where team owner John Fisher and President Dave Kaval want to invest in a privately financed park, they should go for it. Knock themselves out. It could be a win-win for the team and the community.

But if that’s the plan, then it’s time for the city to open the unique and extremely valuable 112-acre Coliseum site the team would be vacating for proposals from all developers.

It’s time to level the playing field — for the A’s to stop suggesting they are entitled to first dibs on development rights for the publicly owned site, which includes the ballpark and Oracle Arena, and for Mayor Libby Schaaf to stop trying to tip the outcome in Fisher’s favor.

Now that Kaval and Fisher have given up on a Coliseum ballpark, they should get in line with everyone else to offer up plans for the site. With the Raiders, Warriors and now the A’s eventually moving out of the Coliseum, bidders will no longer face the constraint of accommodating the teams.

It’s an entirely new ballgame. All options should be on the table, and all legitimate offers should be considered.

The taxpayers are entitled to the best possible price for the land, something that can only be determined through an competitive bidding process. Any appraisal of the value of the unique property would be merely an educated estimate.

The community is also entitled to the best possible development proposal. That can only be found through an open process.

Some have suggested that the A’s need the development profits from the Coliseum site to make the waterfront ballpark pencil out. But, when asked, not even Kaval makes that argument.

Besides, giving Fisher and Kaval exclusive rights to buy the Coliseum site and not putting it out to bid effectively means selling it to them at a discount. In other words, that would be subsidizing the waterfront ballpark with public assets from the Coliseum site.

That sort of shell game would undermine the A’s and Schaaf’s promise that the waterfront ballpark will be privately financed.

Whether the A’s can pull off a privately financed park remains to be seen. Thus far, all we’ve seen are a lot of pretty drawings. But they represent an exciting idea for keeping the team in Oakland.

Now the team needs to figure it out how to pull it off without taxpayers directly or indirectly footing part of the bill.