Leni
The way the courts have dealt in the past with challenges to rulings by sports commissioners (e.g., George Steinbrenner's challenge to the Commissioner of Baseball's decision to oust him as owner of the Yankees). The NBA Agreement, like the MLB Agreement, says that the Commissioner's decision has the force of an arbitration award, which means that any lawsuit is a non-starter.
Yes, Sterling will hire very good lawyers (so did Steinbrenner), and they will make plausible-sounding claims as to why the Commissioner's decision is invalid, but the case will not go to trial.