Donald Sterling is preparing to sue the NBA for $1 billion, according to a report from NBC News.

The report comes a day after it was announced the Sterlings, actually via Shelly Sterling, had reached an agreement to sell the Los Angeles Clippers to former Microsoft CEO Steve Ballmer.

FOX Sports 1/Yahoo NBA Insider Adrian Wojnarowski confirms the NBC report via an email from Sterling's legal representative, Maxwell Blecher.

Sterling also was reportedly found to be mentally incapacitated. However, Blecher told CNN the 80-year-old's diagnosis was of a "modest mental impairment" or a "slowing down."

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