Unlike with Major League Baseball, the taint of steroid scandals never seems to stick.
I'm not saying the NFL is squeaky clean. In fact, I suspect far from it despite the low number of positive tests that surface each season.
The NFL, though, has never suffered the kind of prolonged image problems that continue to plague baseball following Alex Rodriguez's recent admission of use.
Credit that to a BALCO-style cocktail of factors.
First and foremost, the NFL was always far more proactive in trying to address the problem than baseball. This has fostered good will publicly. It took government involvement for baseball to establish a strong drug-testing program in 2005, 16 years after the NFL first began checking players for steroids.
"It's a great advantage for the NFL that Major League Baseball looks like Inspector Clouseau," said Dick Pound, the former president of the World Anti-Doping Agency.
Star power is another factor. The biggest NFL names caught for banned substances in the past decade were Shawne Merriman, Bill Romanowski, Rodney Harrison and David Boston. They were good-to-great players but hardly household names. None had the same cache or record-setting legacies as baseball players as Rodriguez, Roger Clemens and Barry Bonds.
There also is heavy apathy from NFL fans and media about this issue compared to those in baseball. Consider this: There was far more public outrage generated by Spygate than the 2003 Carolina Panthers team that featured six players prescribed steroids and Human Growth Hormone before playing New England in Super Bowl XXXIX.
Still, just because the NFL has avoided a Mark McGwire-sized scandal doesn't make the league impervious.
One may be getting ready to surface. Former defensive tackle Dana Stubblefield was sentenced to two years probation Tuesday for lying to prosecutors investigating BALCO, the Northern California lab that created the previously undetectable steroid known as THG. Stubblefield was one of three NFL players who tested positive in 2003. The 11-year veteran received a reduced sentence by giving federal prosecutors the names of NFL players, agents and trainers he suspected of being involved in illegal drug activities.