This topic is already being discussed in this FanPost, but I thought it was important enough to put something on the front page. Here's the summary of what's happened, if you've missed it.
The TV network Al Jazeera produced a documentary that named NFL star Peyton Manning, among others, in connection with a doping ring that had allegedly supplied him (possibly through his wife) with human growth hormone.
It should be noted that Manning has emphatically denied what was said about him in the documentary, saying he's "furious" and "disgusted." Both teams he's played for, the Colts and Broncos, have backed Manning.