True......here's some additional info on Ryan
New York Jets
Ryan joined the New York Jets of the AFL in 1968. He and Walt Michaels' defensive game plan was instrumental in holding the NFL's Baltimore Colts to seven points in Super Bowl III and earning Ryan his first Super Bowl ring. Seeing the emphasis that Weeb Ewbank placed on protecting Joe Namath and his fragile knees.
Ryan created multiple blitz packages (i.e. the "59 blitz", the "Taco Bell blitz", and the "Cheeseburger blitz") reasoning that the quarterback is the focal point of any offense, and that a defense must attack the offense's strength and centerpiece.
Minnesota Vikings
In 1976 and 1977, Ryan served as defensive line coach for the Minnesota Vikings. The Vikings' defensive line, known as the "Purple People Eaters", was heralded for its ability to punish rivals. The 1976 Vikings won the NFC Championship and appeared in Super Bowl XI. In 1977, the Vikings won the NFC Central and reached the NFC Championship game.
During his time with the Vikings, he started working on a defensive nickel scheme designed to disrupt the passing game. That formed the early basis of the 46 defense.