Photo: Matier & Ross / Oakland Athletics/ Bjarke Ingels Group Photo: Bjarke Ingels Group

The Oakland A’s are set to unveil a “bigger than baseball” mega-ballpark deal that includes a “jewel box” waterfront stadium at Howard Terminal on the city’s waterfront.

The plan would also turn the current Oakland-Alameda County Coliseum site into a tech and housing hub that would keep the Oracle Arena as is, while stripping the massive stadium there down to a low-rise sports park and amphitheater.

“This is a big vision for our city,” A’s President Dave Kaval said.

Kaval said the A’s call for control of both the 55-acre Howard Terminal waterfront site and 111-acre Coliseum site in East Oakland is essential if the team is to deliver on its promise of a “100 percent privately built ballpark.”

The A’s see a downtown ballpark location as the only viable option to excite fans, and generate new ticket sales and revenue needed to make the deal pencil out.

Still, the A’s say sustaining the team for the long term in Oakland will require more money than the proposed 34,000-seat park (the smallest in Major League Baseball) can generate on its own.

“Obtaining the Coliseum makes the odds of Howard Terminal better,” Kaval said.

Developing the Coliseum site would also allow the A’s to honor their commitment that any ballpark deal would include “significant community benefits” for East Oakland residents.

At the center of the proposal is the “jewel box” ballpark at the Port of Oakland’s Howard Terminal, just north of Jack London Square. Kaval describes it as “like nothing you have ever seen.”

Designed by the cutting-edge Danish architectural firm Bjarke Ingels Group, the ballpark is a deliberate throwback to the turn-of-the-century diamonds like Philadelphia’s Shibe Park (a.k.a. Connie Mack Stadium) where the A’s once played.

The ballpark itself would be nestled amid wedge-shaped high-rises — some as tall as 20 stories — with windows looking directly down on the playing field.

The site is too windy for the ballpark to be open to the water, but the stadium would include a publicly accessible rooftop park with sweeping views of the waterfront, Oakland and San Francisco.

“Instead of a ballpark that sits like a fortress, this will be open and accessible to the community at all times” when games aren’t taking place, Kaval said. “It will be a reason to live in the community, activate Jack London Square and become a great landmark in the Bay Area.”

The plan also includes an aerial gondola to shuttle 6,000 fans an hour from downtown Oakland over Interstate 880 and the railroad tracks to Jack London Square. While not shown, the plan would also feature a couple of pedestrian bridges over the tracks — though apparently not an auto bridge.

Photo: Illustrations By Oakland A’s / Bjarke Ingels Group

The Coliseum plan is equally ambitious.

The current 63,000-seat stadium — now home to the A’s and the soon-to-be-gone Oakland Raiders — would be torn down to a nub and turned into a low-rise sports amphitheater surrounded by grassy knolls.

The outer rim of the Coliseum site would feature clusters of development — a mix that could include a tech hub, affordable housing, youth sports complex, light manufacturing and shopping strip.

Oracle Arena, which will soon lose the Golden State Warriors to San Francisco’s new Chase Center in Mission Bay, would continue to host concerts, sports events and other shows.

Photo: Matier & Ross / Oakland A's/ Bjarke Ingels Group

Kaval said turning portions of the Coliseum site into a park would both create a public amenity and avoid the expense of shoring up the site to protect it against the rising sea levels expected in the coming years.

“This is probably the most cost-efficient and effective way to develop it,” Kaval said.

Oakland Mayor Libby Schaaf called the plan for the Howard Terminal ballpark “truly visionary.”

“This is the right project, in the right neighborhood and at the right price to our taxpayers,” Schaaf said Tuesday.

Schaaf also praised the Coliseum plan for offering a framework that “is community-serving,” and called the mix of housing and manufacturing — along with plans to deal with climate change — “a step in the right direction.”

The A’s already have put in an offer to buy the Coliseum site for $137 million. Kaval said the offer isn’t set in stone, and that the team is open to partnering with the city, county or both — even other private interests — to develop the site.

How much public money would be involved for infrastructure at the two sites has yet to be worked out, but Kaval said the plan was to use taxes generated from the projects to cover the major costs.

Photo: Bjarke Ingels Group

The Howard Terminal-Coliseum double play is the second — and possibly last — attempt by the A’s to build a new ballpark near downtown Oakland.

The team’s first pick, which was next to Laney College, died almost as soon as it was announced when the school’s faculty and students objected to putting the ballpark there.

On Wednesday, the A’s plan to announce that they will formally begin a yearlong, state environmental review of the Howard Terminal proposal.

In the meantime, the team is seven months into its exclusive talks with the Port of Oakland for either a lease or purchase option on the property, which is now used largely for storage. The team has an April deadline to strike a deal or lose a $100,000 deposit.

“This is really going to be an important six months as we get into the critical negotiations,” Kaval said.