I forgot to mention it in my daily “Watch This,” but ESPN’s outstanding documentary series “30 for 30” returns tonight (5 p.m.) with “Jordan Rides the Bus,” a film by Ron Shelton (“Bull Durham”) looking at Michael Jordan’s bizarre decision to leave the NBA and play minor-league baseball for a year. Jordan’s unremarkable 1994 season with the Birmingham Barons came after his third straight NBA title and the murder of his father. The question of why Jordan walked away from basketball at the peak of his career has never been adequately explained, to my liking at least. Was it boredom? Burnout? Grief? A top-secret gambling ban from the commissioner? Perhaps we’ll get a little more insight tonight.