Adam Silver is in a tough spot. Silver became the NBA’s fifth commissioner on Saturday. He follows David Stern, whose 30 years as the league’s top executive likely will be unmatched by anyone in any sport. Silver begins his term without facing a major problem that needs immediate fixing or a hot-button issue that requires immediate attention. With TV contracts running through 2016, labor peace assured until at least 2017 and most of the top stars in their 20s, the NBA is