According to ESPN:
New England Patriots quarterback Tom Brady felt trapped this past offseason and was not sure he wanted to play anymore for the only NFL coach he has ever had, Bill Belichick, according to a new book on Belichick’s life.
“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,” a source with knowledge of the Brady-Belichick relationship told ESPN’s Ian O’Connor, author of “Belichick: The Making of the Greatest Football Coach of All Time,” after 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.”
“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 wrote. “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.”
This is the 2nd straight year the Belichick and Brady relationship has tension.