Now his twin brother is doing the talking.
Bills assistant head coach/defense Rob Ryan, hired by Rex this January after being fired by the Saints last November, said in an interview with TheMMQB.com published Friday that the Bills will defeat their long-dominant division rival, the New England Patriots, this season.
"All the respect in the world for Bill Belichick. That was fantastic training, working for him for four years, and I learned a ton," Rob said, referring to the 2000-03 seasons when he was a Patriots assistant coach. "Look, [Belichick] is the No. 1 nemesis of every coach in this league. So it's not just Rex.
"Now, I think if you ask [the Patriots'] offensive staff, the worst they ever play is against Rex. People say, 'Well, [Rex] hasn't beat them [nine of the past 10] tries.' Yeah, well, [Rex] has beat the hell out of that [Patriots] offense. I am sure the respect is mutual.
"But I know one thing, we are going to beat them. We are together, we're going to beat the best. It's two against one. Him one-on-one against any coach in the league, that guy is pretty damn good. And he's also got his best buddy Tom Brady with him. He trained him, and he single-handedly made him great as well."
Rex is 4-11 against New England, including the playoffs, since taking over as the New York Jets' coach in 2009. Overall, the Bills are 4-28 against Belichick since he became the Patriots' coach in 2000.
Later in the interview, both brothers made reference to the declining health of their father, 82-year-old ex-NFL coach Buddy Ryan, as motivation for trying to take down the Patriots this season.
"We're going for broke, man," Rex said.
"Because who knows?" Rob continued. "[Buddy is] not going to be able to watch us coach for much longer, I don't think. But hopefully he can see this one, because we have got big plans. Bring Belichick on. We got him."
Rex might have been more restrained in the interview than his twin brother, but he did make one bold statement that will be sure to catch the eye of Bills fans -- for better or worse.
"I brought in a real football coach, Not a 9-to-5er. A real football coach whose life and passion is the NFL," Rex said of Rob. "The name Ryan means something. If you are a fan of the Buffalo Bills, thank your lucky stars he is here, and myself."