The league and the Maloof family, which owns the Kings, announced Thursday they would support the plan unveiled by Gerry Kamilos, a Sacramento land developer.
Kamilos' proposal involves moving the State Fairgrounds to the Arco Arena site in Natomas, and building a new arena in downtown Sacramento.
His plan was one of seven submitted in response to Mayor Kevin Johnson's request in November. Johnson says the 22-year-old Arco Arena is outdated, and without a new facility, the Kings might leave town.
According to the NBA, the Kings agreed to put $300 million into the project by signing a 30-year lease with an annual rent of $10 million.