Silver spoke Tuesday evening after a meeting of the NBA's Board of Governors. He says he cannot guarantee Donald Sterling will be out as owner of the Clippers because he is fighting the sale.
''It's very difficult to say anything with certainty in a situation like this,'' Silver said. ''I can say with certainty we are doing everything in our power to move Donald out as an owner in the NBA.''
Sterling, who was banned by the NBA for life for making racist remarks, is challenging his wife Shelly's planned sale of the Clippers for $2 billion to Microsoft CEO Steve Ballmer in court. A judge recently delayed the next hearing until July 21, and closing arguments are scheduled for July 28.
When Ballmer originally reached an agreement with Shelly Sterling to buy the team, the planned timeline included an approval vote by the board on Tuesday. But the court case has pushed everything back well past the expiration of Ballmer's offer. The deadline can be extended, and Silver said the league is waiting for the process to play out.
''We're in essence on hold since that sale is being challenged by her husband as to whether she has the right,'' Silver said. ''If the court finds in her favor, the sale will move forward. If not, we will move forward with our own proceedings.''
Before Shelly Sterling agreed to sell the team to Ballmer, the NBA was moving forward with a plan to terminate Sterling's ownership of the team. During the trial, Shelly Sterling testified that she discussed with Silver the possibility of his lifetime ban being reduced to help facilitate a sale of the team.
''It's accurate that we had the conversation,'' Silver said. ''Shelly and I had several conversations over the course of the last few months in which Shelly proposed all kinds of things to me. And frankly it's never been quite clear if she's able to speak for Donald.''
Silver said he asked for a proposal in writing from Donald Sterling, but never received one.
Donald Sterling, who at one point in the proceedings called his wife ''a pig'' in the courtroom, contends she has no right under a family trust that owns the Clippers to single-handedly sell the team. Shelly Sterling contends she has the authority and two doctors hired by her testified that her 80-year-old husband has Alzheimer's disease and is mentally incapable to act as administrator of the trust.
Rather than holding a vote for approval of Ballmer as an owner, the advisory/finance committee met with him.
''We had an excellent session with him and he talked to us about his passion for NBA basketball and his desire and interest in owning the team,'' Silver said.