Atlanta (AFP) - Julian Edelman's Super Bowl-winning display has shone a light on the NFL's anti-doping rules in the wake of the New England Patriots victory over the Los Angeles Rams.

Patriots wide receiver Edelman was named the Super Bowl 53 Most Valuable Player on Sunday after a series of decisive catches during a 13-3 win at the Mercedes-Benz Stadium.

But as the Patriots star prepared to leave Atlanta on Monday for a post Super Bowl trip to Disney World, some commentators questioned whether Edelman should even have been allowed on the field.

Edelman, 32, started the season under the cloud of a doping case, serving a four-game suspension for failing a drugs test which remains shrouded in mystery.

Because the NFL is not a signatory to the World Anti-Doping Agency, the league has its own set of rules for dealing with doping cases.

Whereas an athlete caught doping under the WADA code could face up to a four-year ban for a first violation, Edelman was free to play this season after serving a four-game suspension at the start of the campaign.

Nancy Armour, a columnist for the USA Today national newspaper, contrasted Edelman's treatment with the exclusion from the sport of Colin Kaepernick for protesting against racial injustice.

"The NFL has some warped priorities," Armour wrote. "Call attention to racism and discrimination, and your career is effectively over. Test positive for performance-enhancing drugs, and you can be the Super Bowl MVP."

Others noted the differences between Major League Baseball and the NFL in how athletes sanctioned for drug offenses are dealt with.

Although baseball, like the NFL, is not a signatory to WADA, the league has attempted to crack down on drug use following a series of doping scandals over the past two decades.

- Hall of Famer? -

As well as facing a multi-game ban, any baseball player testing positive for a banned substance would not be eligible to play in the league's post-season that year, heading off the possibility of having a drug cheat named MVP in the World Series.

"Baseball drug cheats are met with pitchforks," the Washington Post's Adam Kilgore wrote on Monday. "(NFL) drug cheats are met with shrugs. They aren't even really considered cheats."

The circumstances surrounding Edelman's failed drug test remain unclear. The substance found in his system has never been publicly disclosed, and it was reportedly not on the NFL's list of banned substances.

Edelman, whose appeal against his four-game suspension was rejected last year, had apologized for the failed test in a statement on his Instagram account.

"I am very sorry –- I don't know what happened," Edelman wrote last June.

"I've taken many, many tests obviously over the course of my career, and nothing like this has ever happened."

What is not in dispute is the impact Edelman had on the Super Bowl, where he once again demonstrated his value to the Patriots with a magnificent display.

Edelman, who missed the entire 2017 season after a suffering a knee ligament injury, finished with 10 receptions for 141 yards and added an eight-yard rush to earn the MVP trophy as well as his third Super Bowl ring.

Edelman, who was also a pivotal figure in New England's comeback win over the Atlanta Falcons in the 2017 Super Bowl by making a miraculous catch during a touchdown drive, is one of only seven wide receivers to earn MVP honors.

Sunday's performance will strengthen claims for him to be inducted into the Hall of Fame, even though his raw career statistics -- he ranks outside the top 100 in all-time receiving yards -- are relatively modest.

Former NFL quarterback Boomer Esiason believes Edelman's record of delivering in big games overshadowed his numbers.

"He is, in my eyes, truly the definition of a Hall of Famer: make the play when the play needs to be made in the biggest games to win the game," Esiason said on CBS Sports.

The issue of Edelman's doping case, however, may complicate his entry. Baseball's Hall of Fame has so far failed to enshrine Barry Bonds and Roger Clemens over their association with the sport's steroid era, despite them being the greatest players of their generation.