Watch the epic new trailer for the Barry Sanders documentary

Coming off a season where he rushed for nearly 1,500 yards, and one season removed from a 2,000-yard MVP campaign, Barry Sanders suddenly retired from the NFL and the Detroit Lions right before training camp in 1999. If not for that earlier than expected retirement, at age-31, it's not a stretch to say he'd be the NFL's all-time leading rusher right now with a couple more seasons on his Hall of Fame resume

Sanders has been around the Lions' organization more in recent years, and he was honored with a statue outside Ford Field earlier this season. But the mystery around his early and sudden retirement has lingered, despite the statement he issued that had a punchline that tried to explain it succinctly.

"The reason I am retiring is simple: my desire to exit the game is greater than my desire to remain in it.”

But why would someone who still had so much left in the tank retire? Why so suddenly? And why in the now old-school style fashion he did, sending a fax to the Wichita Eagle?

Watch the trailer for the Barry Sanders documentary (video)

Back in mid-September, Amazon announced a documentary about Sanders, called "Bye Bye Barry", to be released on Nov. 21, two days before Thanksgiving. Sanders took to Twitter to confirm his year-long collaboration with Amazon and Prime Video, with a confirmation/teaser that "the great mystery of why I walked away will be answered once and for all."

On Wednesday, Prime Video released a longer trailer for "Bye Bye Barry."

The trailer opens with legendary sportscaster Dan Patrick saying "We'll never see somebody like Barry Sanders again." Clips of him that follow prove how unique he was a runner, followed by the speculation and reaction that was out there over why he retired when he did. A lot of familiar faces, including some outside of sports with roots in Detroit and as a Lions fan, were interviewed for the documentary.

"Bye Bye Barry" will debut on Prime Video Tuesday, Nov. 21.