While Peyton Manning prepares for maybe his "last rodeo," the NFL will be conducting an investigation of the human growth hormone allegations that landed at Manning's feet a month ago.

According to the Associated Press, the NFL is in the middle of a "comprehensive review" of those allegations, with league spokesman Brian McCarthy telling the AP that the review was initiated weeks ago.

The results of the review are not expected to be known before Super Bowl 50, which will be played on Feb. 7.

Peyton Manning has denied allegations that he used HGH. (USATSI)

A month ago, an Al Jazeera report linked Manning to HGH, as it was reported that Manning's wife, Ashley, received deliveries of HGH when Manning was recovering from neck surgery as a member of the Colts. In the immediate aftermath of that report, Manning slammed its validity, calling it "complete garbage" while also defending his wife's medical privacy.

Since the allegations were made, Manning has enjoyed a bit of a rebirth on the field after missing a large chunk of the season. And, after helping guide the Broncos to two playoff victories, including one over nemesis Tom Brady and the Patriots, Manning is now on the brink of his second Super Bowl title, which would drastically impact his legacy considering the biggest knock on his record is the lack of a second ring.

However, if the NFL were to find that there's any legitimacy to the HGH allegations, Manning's legacy would certainly take a hit regardless of what happens against the Panthers in Super Bowl 50.