The judge said, "Shelly clearly had the authority to transfer the shares of [the Clippers].
Donald had argued he should never have been stripped of control of the team ... authority she got after 2 doctors determined Donald was mentally incompetent to handle the business affairs of the team.
But the judge begged to differ, concluding the medical examinations were valid and proper.
The judge also pooh-poohed Donald's testimony.
Although the ruling was tentative, it's almost certain it will become final.
TMZ broke the story ... Donald met with Ballmer last week as it became clear he was going to lose his court case. If Donald had some leverage, it's pretty much now lost.