NEW YORK — The NBA is taking a major step toward expansion. The league’s Board of Governors voted Wednesday to approve exploring the addition of new franchises in Las Vegas and Seattle, with plans to make a decision by the end of 2026.

“We need to know by the end of this calendar year what it is we’re doing,” NBA commissioner Adam Silver said in a news conference Wednesday afternoon. “It may not be that every I is dotted, but that would be our goal this year.”

Wednesday’s vote, which required the approval of 23 of the league’s 30 governors to pass, does not mean the NBA will definitely expand to 32 teams. But the league will move forward with a long-expected survey of interested bidding groups to put teams in those two cities, given their history with the NBA.

“You could explore expansion more softly, but it was my view and others’ that we owe it to these markets to be transparent and to be more formal with our approach,” Silver said.

The NBA has danced around expansion for years. Silver said it would be next on the league’s agenda once the NBA completed a new collective bargaining agreement and a new media deal. The former was finished in spring 2023, and the latter was finalized in summer 2024. Now, the NBA can officially look at the marketplace for franchises in Las Vegas and Seattle.

Silver stressed that while Wednesday’s vote advances the process, “nothing is set in stone right now” regarding a league decision on whether to expand. He said that some owners believed the league “frankly, doesn’t need to expand,” though he classified those views as “considerations” rather than “concerns.” Any new expansion team would begin play in the 2028-29 season at the earliest.

An executive from one team told The Athletic that their preference is expansion rather than relocation, believing the two markets, especially Seattle, will bring increased revenues over the long haul that would negate any concern about the franchise receiving 1/32 of future media rights revenue versus the current 1/30th share.

“This is definitely going forward,” the executive said.

Potential bidders, government officials and sports finance executives have been anticipating the league’s decision for years and were not surprised by Wednesday’s vote.

“I think it’s going to be a go,” Las Vegas mayor Shelley Berkley told The Athletic earlier this week. “I am looking forward to welcoming the team when it gets here. This is exciting. This is exciting for Las Vegas, and it’s going to be great for the locals, too. … We are ready to get a professional basketball team.”

“Seattle is ready to welcome the Sonics home. We never stopped being a basketball city, and the fans have never given up,” Seattle mayor Katie Wilson said in a Wednesday statement before the vote. “You see it in our parks, in our schools, in packed gyms in every neighborhood, and in our Seattle Storm championships. We built a world-class arena. We have a strong economy and a dedicated workforce. We are prepared, we are united, and we are ready for the next chapter of our Sonics.”

While Silver said Wednesday there was “absolutely a chance expansion may not happen,” he admitted the league expects “enormous interest” from Seattle and Las Vegas. The Athletic reported Wednesday that Silver, according to a source with knowledge of discussions among ownership, has told league governors he expects expansion fees to run between $7 billion and $10 billion per franchise. Both Las Vegas and Seattle have made strong cases to the NBA and have fans waiting for the league’s arrival.

“At least standing here today, there’s nothing that I can see in the relatively short-term future of this league that would indicate in any way that there won’t be enormous interest in those markets, and that the board will continue to support moving forward,” Silver said. “I should say, at the right time, it requires 3/4 of the owners supporting it. But we wouldn’t be moving into this step (unless there was interest).”

“And in fairness to parties that are interested, that was one of the reasons we wanted to make this formal announcement, because wherever those values end, it’s an enormous undertaking. It’s generally not just a single owner, it’s a group, it requires financing, it requires arena planning, etc.”

The NBA has not expanded since 2004, when the Charlotte Bobcats joined the league. In that time, the NHL has added two teams — in Las Vegas and Seattle. The NFL has not expanded in that time, but the Raiders moved from Oakland, Calif., to Las Vegas in 2020 and built a new stadium. Major League Baseball will also move a team to Las Vegas; the Oakland Athletics are expected to arrive in 2028, which is when the potential new NBA franchises could begin play.

An NBA team, if it gets to Las Vegas, would be the fifth professional sports team in the market, along with the Raiders, Athletics, Golden Knights and the WNBA’s Aces. In the past, Silver has referred to the city, which hosts the NBA Summer League and the NBA Cup semifinals and championship, as “our 31st market.” Previous editions of the G League Showcase have also been held in Las Vegas. That has only strengthened the relationship between the league and the city.

“I’m very excited to see the NBA advance this process toward a Las Vegas expansion team,” Nevada Gov. Joe Lombardo said in a statement after the vote. “I look forward to continuing conversations (with) Commissioner Silver and league officials to ensure this expansion delivers lasting benefits for the state of Nevada.”

Berkley said she is aware of at least three groups that have shown interest in bringing teams to Las Vegas. One is run by NBA Hall of Famer Magic Johnson, who recently met with Gov. Lombardo and other officials, according to the Las Vegas Review-Journal. Another, she said, includes LeBron James, though he said this month that he is no longer interested in bidding on an NBA team, as first reported by The Athletic. And another group, Berkley said, is led by a local businessman she did not wish to name.

While Vegas seems ready for an NBA team, Seattle has been waiting for a franchise since 2008, when the SuperSonics relocated to Oklahoma City and became the Thunder. Seattle is the second-largest American media market without an NBA team, after Tampa, Fla. If Seattle gets a team, the Sonics’ history, logo, team name and intellectual property will return to the city.

Samantha Holloway, owner of the NHL’s Seattle Kraken, has already made it known that she wants to bring an NBA franchise back to the Emerald City. Holloway created an umbrella company this week for the Kraken and its home, Climate Pledge Arena, as well as other properties, in an effort to “oversee a growing portfolio of properties and fuel new opportunities.”

Silver stressed that the process to identify other potential bidders or markets remains open. He also reiterated it’s possible there could be expansion for only one team, if any at all, by the time the process is done.

“So everyone understands, there’s been no handshakes on the side,” he said. “No commitments.”

– The Athletic’s David Aldridge contributed to this report.