The last couple of years appeared to be a turning point in the relationship between Patriots coach Bill Belichick and quarterback Tom Brady, according to a new book about Belichick's life. ESPN's Ian O'Connor spent three years and spoke to 350 people for Belichick: The Making of the Greatest Football Coach of All Time, due out September 25. He did not, however, speak with the eponymous subject.

The resulting pages reveal a Pats team whose leaders seem to perpetually be on the cusp of a final fissure. Despite the headline-grabbing snippets that have leaked from advance copies, the fractured relationship between coach and QB isn't that surprising, even if the Pats issued a statement denouncing reports of their dicey relationship

"Tom knows Bill is the best coach in the league, but he's had enough of him," a source told O'Connor, by way of ESPN. "If Tom could, I think he would divorce him." The partnership between player and coach was extended further with the marriage metaphor: "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 rift between star QB and coach appeared ready to turn into a serious breach in the late winter:  “I was told by a number of sources that as late as late March," O'Connor told Scott Van Pelt on SportsCenter, "Brady wasn’t sure he was going to play again for Belichick.”

As had been alluded to in the past, it's the drafting of Jimmy Garoppolo—now with the Niners—that may have doomed the alliance at the top of the Patriots pecking order. Especially when Belichick appeared to liken Brady to a cog in his team's football scheme, instead of the greatest quarterback of all time.

"But once Belichick drafted Garoppolo in 2014, and said that—he cited Tom’s age and contract status—‘I’d rather be early than late at that position,’ it made it inevitable and it happened last year,” O'Connor says. Tom's family saw it, too. Brady's sister, Nancy, is quoted in the book as saying, "Belichick will definitely do to him someday what the Colts did to Peyton [Manning]." However, after the Garoppolo trade, Brady came back in the fold:

"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 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."

There are other revelations in the book, including how Belichick had "serious doubts" that Brady wasn't somehow involved in the Deflategate scandal that led to his four-game suspension at the start of the 2016 season. Likewise, Brady's tepid defense of himself—"I don't believe so," when asked if he was a cheater—actually stemmed from his suspicion the Spygate scandal against the Jets had some truth to it. 

There's a host of revelations in the book, including Florida coach Urban Meyer warning at least one NFL team about drafting his troubled TE Aaron Hernandez, and Belichick's checkered relationship with Bill Parcells, Nick Saban, and his dad, Steve Belichick. You can see why the stridently private coach didn't want to talk with O'Connor.

The Patriots are 1-1 so far this season after losing in Week 2. But the release of O'Connor's book will likely be their biggest L of the season.