NFL Countdown: Bill Belichick's sensational U-turn on New York Jets remains one of league's biggest what-ifs

New England Patriots head coach Bill Belichick is one of, if not the greatest, head coach of all time. He has won six Super Bowls with the AFC franchise. He is regarded as one of the best defensive minds in the game.

Before he was the super coach of the Patriots, he was the head coach of their division rivals, the New York Jets. For today's NFL Countdown, we take a look at one of the most perplexing incidents that happened involving the 70-year-old during his time in the NFL.

Belichick was the New York Jets head coach....for a day

He was groomed to be Bill Parcells' natural successor, and many thought it was a good move. Parcells moved to the Patriots after the 1999 season, leaving Belichick to take over from then on.

Belichick was an assistant head coach and defensive assistant during his time there and was slated to take over the Jets. But that was when one of the most intriguing things to ever happen with the now-Patriots coach took place.

Belichick completed a workout and was then seen walking out of the facility with his briefcase per ESPN.in, which was an odd time for the coach to be leaving. Then shortly after, a press conference was announced and Belichick took center stage, but it was not for the reason that many of the media had gathered there for.

The coach infamously wrote his resignation letter on a piece of paper (not the most professional thing to do). Then, he reportedly gave it to the organization.

What made the situation even stranger was that, not long after, Belichick was announced as the New England Patriots head coach. Coincidence? Given that the now 70-year-old was under contract, the Jets received the Patriots' first-round pick in the 2000 NFL Draft.

The whole situation was just puzzling. After being an assistant for two years and when the opportunity finally came to be the main man, it was thrown away in favor of joining the franchise's direct rival.

What if Belichick had stayed with the Jets?

What if the head coach had stayed with the AFC franchise? Photo via Pittsburgh Post-Gazette.

Hindsight is a wonderful thing, isn't it? After his move to New England, the 70-year-old rose to prominence with Tom Brady and was part of, perhaps, one of the most dominant eras in football. It yielded six Super Bowls across two decades and countless Championship games and division titles, but what if Belichick had stayed with the Jets?

We know that the Jets have essentially been a basket case since 2010 after they lost back-to-back AFC Championship games to the Colts and Steelers. Their one and only Super Bowl came back in 1968, and it seemed like it was a long time until the playoffs were reached again.

Had the 70-year-old stayed on as head coach of the Jets, who knows how it would have played out. Would the team have had the same success as the Patriots? Would they have won multiple Super Bowls? Would Tom Brady be "Tom Brady" or just another player in the league?

The Jets came off a 8-8 in 1999. Then, the team proceeded to play in the playoffs in two of the next three seasons, so the talent was there for the head coach. It remains to be seen if that would translate into success.

The situation was just bizarre, and it is still not known to this day what made the 70-year-old flip on the Jets and go to the Patriots. However, one thing is for sure, Jets fans surely wished he had stuck around.