One year, it's Deflategate, the next it's Peytongate. Denver Broncos quarterback Peyton Manning enters the Super Bowl and possible retirement with an investigation hanging over his head over whether he received human growth hormone while he was rehabilitating injuries four seasons ago. The US Anti-Doping Agency, best known for nabbing Lance Armstrong, confirmed Thursday it was helping the NFL in its ongoing, comprehensive review of Manning's case. USADA was also working with Major League Baseball, which had players implicated in the Al Jazeera report last month that linked Manning to a clinic that deals in HGH. "I do welcome it. It's no news to me," Manning said of the investigation, as the Broncos got back into their practice routine in advance of the Super Bowl next week. Is the story a distraction as he prepares to play the Carolina Panthers? "Not at all," he said. Last month, Al Jazeera reported that an intern at an Indianapolis anti-aging clinic was secretly recorded suggesting that in 2011, Manning's wife received deliveries of HGH, which is banned by the league. Manning, then with the Colts, was rehabbing from neck surgeries. The intern, Charles Sly, recanted the story. At the time, Manning angrily denounced the report, calling it "completely fabricated, complete trash, garbage," and insisted he never took shortcuts in his difficult return to American football after missing 2011 with neck problems. Still, faced with the report, the NFL was obligated to look into it. Though no conclusion is expected before the Super Bowl, the resetting of the Manning investigation gives the NFL cover from those who suggest the league plays favorites. A year ago, Tom Brady and the New England Patriots were in the crosshairs of "Deflategate" — an investigation about under-inflated footballs that bordered on ridiculous, but nonetheless roiled Super Bowl week, then extended well beyond. Manning's welcoming of the probe into him is his way of saying he's sure the league won't find any wrongdoing. And yet, the fact that the league did not have a testing program in place for HGH in 2011, and that the program it adopted is seen by some in anti-doping circles as having deficiencies, could be viewed as a disservice to Manning as he tries to show he's innocent. USADA CEO Travis Tygart wouldn't comment on Manning's case directly, because USADA was involved. But, he said, "athletes deserve to have the best anti-doping program in place to protect their rights, and if questions come, to be able to say, ‘Hey, I'm clean, I did it right and I'm held to the highest standards.' Anything less really lets down athletes, and they deserve more." — AP