Tom Brady admits his departure from Patriots was due to Bill Belichick

Tom Brady knew his tenure with the New England Patriots was over before it officially ended.

In the upcoming documentary "The Dynasty," the former Patriots quarterback shared that he knew he wasn't going to return to New England as a free agent in 2020 with Bill Belichick remaining as the head coach.

"Me and coach Belichick, we did what we loved and competed for 20 years together," Brady said, as transcribed by The Athletic. "But I wasn't going to sign another contract [in New England] even if I wanted to play until [I was] 50. Based on how things had gone, I wasn't going to sign up for more of it."

The documentary, which details the Patriots' 20-year dynasty run to six Super Bowls and other successes, also focused on how the Brady-Belichick relationship deteriorated and why the quarterback didn't end his career in New England, according to The Athletic. Notable Patriots players such as Rob Gronkowski, Matthew Slater and Wes Welker reportedly explained the difficulties of playing for Belichick and how "brutal" Brady was treated by the end.

Robert Kraft also reportedly shared that Brady confided with him over Belichick's treatment.

"Tom and I had a number of discussions about how Bill treated him," the Patriots owner said, as transcribed by The Athletic. "Tommy is very sensitive. He was always looking for Bill's approval, almost in a father-son kind of way. And that's not Bill's style ever to give that."

There were reports that emerged over Brady's final few seasons in New England stating there was growing angst between him and his head coach. The Patriots drafted Jimmy Garoppolo in the second round of the 2014 NFL Draft, which was believed to be a possible root of the friction between Brady and Belichick. 

Even though the Patriots traded Garoppolo in the middle of the 2017 season, Brady didn't get a multiyear extension he sought after the trade. He signed a two-year, $70 million contract during training camp of the 2019 season, but the second year of the contract was a void year that allowed him to become a free agent. The Patriots weren't allowed to franchise tag him, either.

Brady signed with the Tampa Bay Buccaneers on a two-year, $50 million contract in 2020 after 20 seasons with the Patriots, winning his last Super Bowl with New England just 13 months prior to his departure. The future Hall of Fame quarterback added to his legacy in three seasons in Tampa Bay, winning a seventh Super Bowl title in his first season with the Buccaneers.

While Brady grew tired of Belichick by the end of his Patriots tenure, he's recently spoken more fondly about his former coach. He penned a thoughtful social media post when the Patriots opted to part ways with Belichick in January, writing that he was "incredibly grateful to have played for the best coach in the history of the NFL."

"I could never have been the player I was without you Coach Belichick," Brady wrote in an Instagram post at the time. "I am forever grateful. And I wish you the best of luck in whatever you choose next."

Brady also came to Belichick's defense after his former head coach wasn't hired in the recent coaching cycle.

"I'm not one to hire. I don't know the criteria for hiring these guys, for hiring coaches you know. I've never been a part of it," Brady said on his "Let's Go!" podcast earlier in February. "I mean I'm surprised that the greatest coach ever doesn't have a job, you know, absolutely. You know I'm surprised about a lot of things in the NFL. When I was a free agent, there was a lot teams that didn't want me.

"There's a lot of things that happen that, for one reason or another, don't go exactly the way you think they should go."