The Pistons aren’t in the playoffs for the fourth straight season and they’ve been irrelevant for a lot longer, as they’re almost 10 years removed from their championship season under Larry Brown. It’s been a long run for team president Joe Dumars, but league sources say that Dumars’ reign will soon be coming to a close. Dumars is so entrenched and such an iconic figure from his playing days, we’ll believe it when we see it. But it sure sounds as if he’s on his way out, along with Lawrence Frank, who is finishing his second season as coach. Six other coaches are expected to be sent packing when the season ends Wednesday, with the Sixers’ Doug Collins and Cleveland’s Byron Scott heading the list. The Sixers have grown weary of Collins, who still has a year left at $4.5 million. They’re hoping he quits. The Cavs are headed for their third consecutive last-place finish in the Central Division, a franchise first, and Scott is going to take the fall.