According to a passage in Belichick: The Making of the Greatest Football Coach of All Time, a source with knowledge of the dynamic between Brady and Belichick intimated Brady isn't enthused by the prospect of playing for the 66-year-old anymore.
"If you're married 18 years to a grouchy person who gets under your skin and never compliments you, after a while you want to divorce him," the source told author and ESPN reporter Ian O'Connor following the 2017 season.
"Tom knows Bill is the best coach in the league, but he's had enough of him. If Tom could, I think he would divorce him."
Brady's sister, Nancy, also reportedly told people Tom was concerned "Belichick will definitely do to him someday what the Colts did to Peyton [Manning]."
Brady skipped organized team activities in May and told Jim Gray, "I plead...the Fifth!" during an offseason sitdown when asked if he felt appreciated for all he has accomplished in New England.
"But in the end, even if he wanted to, Brady could not walk away from the game, and he could not ask for a trade," O'Connor writes. "The moment Belichick moved [Jimmy] Garoppolo to San Francisco, and banked on Brady's oft-stated desire to play at least into his mid-forties, was the moment Brady was virtually locked into suiting up next season and beyond. Had he retired or requested a trade, he would have risked turning an adoring New England public into an angry mob."
O'Connor's deep dive follows a lengthy report by ESPN.com's Seth Wickersham in January that explored the growing discord between the two pillars of the Patriots franchise, their differing attitudes toward Brady's trainer, Alex Guerrero, and his role with the club.
Additionally, Wickersham reported Brady and Belichick held separate meetings with owner Robert Kraft last season that resulted in Jimmy Garoppolo getting traded to the San Francisco 49ers, much to Belichick's dismay.
Incidentally, O'Connor writes Brady grew worried about his grip on the starting job when the Patriots drafted Garoppolo in 2014—a feeling that has been chronicled for years.
"If you talk to people close to Brady, one thing he has feared for a long time is anyone taking a snap instead of him," NFL Network's Ian Rapoport said in 2015 during the Deflategate saga.
To that point, O'Connor spoke to a Patriots assistant who said the coaching staff doesn't think of Brady in glowing terms: "I don't think the coaches view Tom as special as everyone else in football does. Mr. Kraft thinks Tom is the greatest gift ever, but the coaches don't."