The Seattle vs. Sacramento showdown is set.

The NBA received an official offer Friday from 24 Hour Fitness founder Mark Mastrov and billionaire Ron Burkle to buy the Sacramento Kings and keep the team from moving to Seattle, league spokesman Tim Frank said. No financial details of the proposal have been released.

Sacramento Mayor Kevin Johnson announced the Mastrov-Burkle bid during his State of the City address Thursday night, calling it a "competitive offer." Johnson tweeted Friday: "The proposal is IN!! A proud day for Sacramento!!"

The Associated Press has reported since Jan. 22 that Mastrov and Burkle were working on a plan to keep the Kings from relocating to Seattle.

Johnson finally announced the proposal publicly on the eve of his self-imposed March 1 deadline. With the league confirming the prospective Sacramento buyers, the only major announcement left is the future owners — and location — of the franchise.