If you will, a case study:
August 3, 2005: Baseball's Rafael Palmeiro is suspended after testing positive for steroids. From Michael Wilbon: "Oh yes, baseball is facing a crisis. In this current climate of suspicion, is it fair to start looking at any pitcher with biceps with increased skepticism, too? Well, maybe it isn't fair. But that won't stop anyone. And where, exactly, is the commissioner of baseball while such an obvious crisis breaks out? Apparently hiding under his desk."
October 23, 2006: The NFL's Shawne Merriman is suspended after testing positive for steroids. From John Clayton: "The four-game steroid suspension of Chargers linebacker Shawne Merriman really comes at a horrible time for the team. Linebacker Shaun Phillips is expected to be out four to six weeks with a calf injury. They've lost linebacker Steve Foley for the season. The only outside linebacker of note is Marques Harris or Nick Speegle, which might the Chargers move Tim Dobbins or Donnie Edwards to the outside."
The NFL, it's like the Teflon Don, really.