Among the greatest athletes in American team sports, Tom Brady took the unlikeliest and most-doubted road.

Wayne Gretzky was a legend by age 10. Kareem Abdul-Jabbar was a star in high school, when he was known as Lew Alcindor. LeBron James was a high school star too, with highly publicized national television appearances. Alex Rodriguez and Barry Bonds were well-known before ever stepping in an MLB batter's box.

Many Michigan fans wanted Drew Henson playing over Tom Brady. Plenty of New England Patriots fans probably didn't even know of Brady, a sixth-round draft pick, when he replaced an injured Drew Bledsoe.

There's a well-worn, and partially embellished, story of Michael Jordan being cut from his high school varsity team. That helps the legend of Jordan becoming an unlikely star. It ignores that Jordan was a national player of the year at North Carolina and while he shouldn't have slipped in the NBA draft, being picked third overall isn't bad.

Brady is the epitome of the out-of-nowhere superstar story. None of the other GOAT candidates in sports have quite Brady's underdog story. We're very unlikely to see it repeated.

Nearly 200 draft picks went before Tom Brady

The quarterback with the greatest resume in NFL history went 199th in the draft. You've heard that a few hundred times over Brady's career.

It's still worth telling again because this is the actual fairy tale that we like to create. Look at a random NFL depth chart and pick a backup QB who was barely drafted, then project him to win seven Super Bowls and become the NFL's all-time leader in passing yards and touchdowns. Or pick a quarterback at a big-name college program struggling to hang onto his starting job over a hot recruit and imagine him making 15 Pro Bowls. It seems impossible because, practically speaking, it is.

Brady's story might seem like one of many unlikely star stories — Joe Montana being a third-round draft pick and beginning his career behind Steve DeBerg, or Mississippi Valley State's Jerry Rice overcoming too many drops as a rookie to be a legend with the 49ers, or Kurt Warner going from bagging groceries to winning a Super Bowl — but it's unlike any other we've seen. Brady had almost no pedigree. He was closer to being out of the NFL than developing into a star. Then he did things nobody ever had in professional football.

Brady is simply the greatest underdog success story in American sports history. Even if, for most of his career, nobody wanted to hear it.

Brady then became the NFL player everyone loved to hate

At some point, Brady became an NFL villain. It never made sense because Brady has never come off as a bad guy. Maybe it was deflategate, though that was a misdemeanor at worse and never proven beyond a doubt anyway. Most people didn't even know why they disliked Brady. As the Patriots kept winning, the bitterness grew.

It started to change the past two seasons. Brady moved on to the Tampa Bay Buccaneers and was removed from the corporate coldness of the "Patriot Way." It became harder to hate Brady. And it became practically impossible to deny his accomplishments. Going to another franchise and immediately winning another Super Bowl at age 43 is beyond unprecedented. It's something else Brady did that might never be replicated.

Perhaps there's a future undrafted NBA player who will surpass Jordan, someone who takes a while to establish himself as a starter who will beat Bonds' home-run record or even another sixth-round quarterback who will go to 10 Super Bowls.

You just shouldn't count on it. Brady's NFL career was once in a lifetime.