The New York Post reports associates thought Sterling, 80, would die from the disease two years ago.
Other league owners will determine he can be forced to sell the Clippers. Sterling is expected to put up a fight.
Those expressed interest in buying all or part of the team include Oprah Winfrey, Sean Combs and Sterling's estranged wife, Rochelle "Shelly" Sterling, who has been accused of racism and discrimination in the past.
But an NBA official said the players and league are looking for a complete change in ownership.