SAN FRANCISCO (Map, News) - There are more balls in the air, but the 49ers’ focus in their quest for a new stadium remains on the Santa Clara plan.

In the last week, it was revealed that the 49ers and Brisbane have talked about including a study on a stadium site as part of a proposed development by Universal Paragon Corp.

“That site was part of our discussions earlier,” said Lisa Lang, vice president of communications for the 49ers. “Now, it’s up to [Brisbane] to decide whether they want to go ahead with that. If they do, we’ll provide them with the relevant information from our side.”

Meanwhile, San Francisco is moving forward with its plan for development of Hunters Point. Proposition G — a proposal for Lennar Corp. to provide a mix of retail and housing, 25 percent of it affordable housing — will be on the June ballot in San Francisco. There will be a spot for a stadium in that plan, though Lennar has said it could go ahead with or without the stadium.

As usual with San Francisco politics, there will be a competing proposal, Proposition F, on the ballot, which would mandate that any housing project include 50 percent affordable housing.

“It’s a feel-good thing,” said Carmen Policy, a Lennar spokesman and former 49ers president, “but the reality is that no developer would go in there under those restrictions because he couldn’t make money.”

The 49ers, though, continue to look on the Hunters Point project and now Brisbane as backups for the Santa Clara plan. They are in negotiations with Santa Clara and Cedar Fair, owner of the Great America theme park.

Originally, the plan was to build the stadium in the main parking lot of Great America. Now, the plan is to build it in an auxiliary parking lot opposite the 49ers’ practice facility. City Manager Jennifer Sparacino has written a letter to Cedar Fair saying that the city has the right to do that if it replaces the available parking.

The 49ers may also buy Great America. When that possibility first surfaced, Cedar Fair denied it. but Peter Crage, the company’s chief financial officer, has since admitted that the proposal came from his firm. (Lang confirmed that in a private meeting I had with 49ers officials.)

Santa Clara officials and the 49ers are negotiating a “term sheet” for the stadium to present to the City Council.

“We want that by June or July,” said Assistant City Manager Carol McCarthy, who said talks are on schedule. “That’s a long lead time for a November election, but it will take time to get it phrased right for a ballot imitative.”

The proposal includes an added tax to visitors to the hotels in the area, which hotel owners have endorsed enthusiastically, Lang said, because they anticipate added business if the stadium is built. The 49ers need Santa Clara’s participation because a combined public-private plan will be necessary for them to get financial help from the NFL.

The Yorks will still have to pay by far the largest share of the estimated $913 million cost, which would be the biggest check ever written by an NFL owner. Lang is confident they will. I’m very skeptical. But one thing is certain: Wherever a stadium is built, it won’t happen unless that check is written.

Glenn Dickey has been covering Bay Area sports since 1963 and also writes on www.GlennDickey.com. E-mail him at glenndickey@hotmail.com.