Tom Brady
Everybody knows how Brady came out of nowhere to become the best player in NFL history. The Patriots made him a sixth-round pick in 2000 and he became their fourth-string QB. Drew Bledsoe was their highly-paid starter but an injury handed Brady a massive opportunity in his sophomore year. Suddenly, Bill Belichick threw the Michigan starlet into action.
It became a truly iconic season because Brady demonstrated maturity beyond his years. He ousted Bledsoe and convinced Belichick that he was the man to lead the franchise forward into their bright future. Meanwhile, he became the youngest Super Bowl-winning quarterback ever. We all know what happened over the next couple of decades as Brady became the quarterback with the most Super Bowl rings in NFL history. But it was an amazing beginning overall (via Indy Star).