Sterling's attorneys called only two witnesses during the emotionally charged trial that will determine whether the 80-year-old real estate billionaire' s wife had the authority to sell the Clippers to former Microsoft Corp chief executive Steve Ballmer.
A neurologist called by Sterling's attorneys testified that Sterling, who has been banned by the NBA for racist remarks, was under undue stress from his wife Shelly Sterling, 79, while taking the mental exams that declared him incapable of managing his business affairs.
"There is a stress in the relationship between Mr. and Mrs. Sterling, and you wouldn't want that stress to impact a mental status investigation," neurologist Jeffrey Cummings told Los Angeles Superior Court.
Sterling was removed as the trustee of the family trust that owns the Clippers after physicians in May deemed him to be suffering from early Alzheimer's disease.
His legal team was dealt a blow last week when Judge Michael Levanas refused to let them call Shelly Sterling's attorneys as witnesses.
They contend Shelly Sterling, her attorneys and the NBA hatched a secret "Plan B" to gain control of the team when Sterling refused to sell the Clippers amid public and financial fallout from his racist remarks.
"This is a ploy," Sterling's attorney Bobby Samini said outside court, adding he believes Shelly Sterling intends to divorce. "She wants control of the entirety of the estate."
Sterling's attorneys chose not to call either Sterling to testify. Both testified earlier in the trial, with a combative Donald Sterling often shouting and at one point calling his wife a pig.
Cummings, a physician who specializes in dementia at Cleveland Clinic in Las Vegas, said he would have told Sterling why he was being examined, supporting Sterling's argument that he was misled into the medical examinations.
But under cross-examination, Cummings testified it would be adversarial if a physician told a patient the legal implications of an examination.
Cummings is central to Sterling's case that the process used to remove him as trustee was inappropriate, but Levanas said he was unsure whether Cummings's testimony - much of which was successfully objected to by Shelly Sterling's attorney - would factor in his decision.
Closing arguments begin on July 28 and Levanas will rule on whether Sterling was properly removed as a trustee and if Sterling's revocation of the family trust after the sale to Ballmer could void the NBA-record deal.
Levanas will also decide whether the sale can continue pending a possible appeal.
Sterling has launched other lawsuits against the NBA, league commissioner Adam Silver and Shelly Sterling in a bid to scrap the sale, which he testified undervalued the team.
Sterling is likely to ask a civil court for an injunction on the sale if he loses the probate trial.