The Kings' asking price would top the NBA-record $450 million the Golden State Warriors sold for in July 2010. Johnson said he's had past discussions with more than one group about possibly stepping forward as owners if the Kings were up for sale.
"All indications that I have seen and read and heard is they are exploring opportunities to sell the team, and that is public and that is the first I have ever heard," Johnson said. "We need to put ourselves in a position to find an ownership group and buyers to keep the team here in Sacramento."
Johnson said he had not spoken with any members of the Maloof family or NBA Commissioner David Stern on Wednesday.
News of the discussions came a day after officials in Virginia Beach, Va., announced they were dropping their efforts to build a new arena. Virginia Beach had been reported as a relocation option for the Kings.
The Maloofs backed out of a tentative $391 million deal for a new downtown arena with Sacramento last year, reigniting fears the franchise could relocate. Johnson and the Kings broke off all negotiations in the summer with the Kings, saying the deal didn't make financial sense for the franchise.
In 2011, the Kings appeared determined to move to Anaheim before Johnson convinced the NBA to give the city one last chance to help finance an arena. At one point, Johnson seemed so certain the team was gone he called the process a "slow death" and compared the city's efforts to keep the Kings a "Hail Mary."
Johnson made a desperate pitch to the NBA Board of Governors in April 2011, promising league owners the city would find a way to help finance a new arena to replace the team's current outdated suburban facility. That pitch bought the Kings time, before the brokered deal between the city and the Maloofs fell apart last year.
Johnson said the Maloof family still must repay a $77 million loan to the city and other lenders.
While some players around the league took to Twitter on Wednesday to express their excitement about the possibility of the NBA returning to Seattle — especially those players from the Puget Sound area — others were more reserved.
"There's a part of me that's disappointed because Sacramento, I've enjoyed my times. I think Sacramento is a great town," said current Denver coach and former Seattle coach George Karl. "I'm not going to lie — I'm happy that Seattle is going to have a team more than Sacramento. But I am disappointed that Sacramento can't keep their team."
AP Sports Writers Bernie Wilson, Antonio Gonzalez, Pat Graham and Brian Mahoney, and AP Writer Don Thompson contributed to this report.