The 2017 NFL season began with the New England Patriots coming off the greatest Super Bowl comeback victory of all time—they beat the Atlanta Falcons in overtime 34-28 after trailing 28-3 in the third quarter.
The Patriots' quarterback room that preseason consisted of a 40-year-old Tom Brady, 25-year-old Jimmy Garoppolo and 24-year-old Jacoby Brissett.
Today, not one of them is still on the Patriots, but each had a major role in shaping the current quarterback situation around the league.
Tom Brady is a Tampa Bay Buccaneer, but how did we get here? It all started three years ago, when the Patriots were the kings of the NFL.
Bill Belichick, architect and head coach of the Patriots, knew he had something special in his quarterback room with Brady, Garoppolo and Brissett.
"We used to call him about once a week back then asking if he'd move one of them," says an NFL executive whose team needed a quarterback. "And we weren't alone, either."
Belichick had a good roster and five Super Bowl wins. But the Patriots had an uncertain future with Brady aging and the rest of the roster needing to be turned over.
In his quarterbacks, he saw valuable trade capital.
Brissett would be the first to go. Andrew Luck's shoulder injury caused the Indianapolis Colts to trade wide receiver Philip Dorsett for him in early September. But Belichick still had Brady and the player many around the league believed he was grooming for the future—Garoppolo.
September became October, and the NFL's trade deadline loomed.
"We were calling Bill once a week, I swear to God, trying to get Jimmy," says a current director of player personnel. "You might not remember this, but at the time, no one loved the  quarterback class in the draft, and Garoppolo was set to be a free agent. Common sense says you trade him. And Belichick is the best at this—shipping off guys for draft picks—so we thought it would be an easy trade."
Yet as the Oct. 31 trade deadline approached, Garoppolo was still a Patriot.
"I remember getting down to the wire and telling our QBs coach that we'd just make a run at Jimmy in free agency," says the player personnel director.
The Patriots sent Garoppolo to the 49ers for the shockingly low price of a second-round pick. Belichick, Brady and owner Robert Kraft were left in a triangle of frustration that led to this week's development of the greatest quarterback of all time leaving his NFL home of 20 years.
How do we get from a trade in 2017 to Brady leaving for Tampa Bay?
At the time, there was an incredible amount of buzz around the NFL that the 49ers originally asked for Garoppolo, but Belichick instead offered Brady. A Patriots source confirms that's how it went down, and a 49ers source close to John Lynch says the first-time general manager couldn't believe his ears when he heard the counteroffer.
Lynch had the chance to trade for the best quarterback ever to play and bring him back to his hometown? It's the ultimate no-brainer, but it didn't happen.
"Kraft shut that s--t down fast," says a source close to Belichick. "So, instead, Lynch gets Garoppolo, but Brady, Belichick and Kraft haven't been the same since Tom learned that Bill was ready to get rid of him. And that lit a fire under his ass."
Brady, the GOAT, fueled by a perceived slight that his head coach wanted to trade a 40-year-old and keep his backup? Yeah, that sounds right.
"You have to remember, this guy has a chip on his shoulder the size of Mount Everest," says a former player who knows Brady well.
And every move of Brady's since that late October meeting of the Patriots' holy trinity has been preparing for this moment, speculates his former teammate.
Brady and the Patriots lost to the Philadelphia Eagles in Super Bowl LII. That offseason, he and the team agreed to a new contract and tore up his existing deal that would have expired after the 2019 season.
Brady and Belichick earned their sixth Super Bowl ring during the 2018 season, this time with a win over the Los Angeles Rams. The following offseason, Brady and New England again redid his deal. This time, Brady restructured the contract to give the Patriots much-needed cap space.
At the time, many believed he was freeing up space for the team to add weapons. Those who know Brady don't believe this.
"He tore up deals after '17, after '18, and got it so the Patriots couldn't [franchise] tag him. Dude was planning this day all along," speculates another former teammate. "I could have predicted in October 2017 that this day was coming."
At the start of the 2020 NFL league year, the house of cards Brady set up fell in on the Patriots. According to multiple reports, Brady made no calls to the Patriots to work on a deal for the upcoming season. Instead, he waited for his suitors to line up and picked the best situation for himself and his family.
Brady got to Tampa after a stone-cold wait for free agency and for a contract that kept New England from franchise-tagging him. It was shrewd, but it shouldn't have been unexpected from a quarterback who made a living picking apart defenses with poise and a chess-like ability to plan ahead.
The Patriots are now left without any of the quarterbacks they had stockpiled just two-and-a-half years ago. And the moves they made in that 2017 season led to the breakup of the greatest quarterback/coach duo in NFL history.
Matt Miller covers the NFL and NFL draft for Bleacher Report.