McCarthy also had something to do with developing and teaching QB including Rodgers who was still a backup in GB when he took over.
Coach Mike McCarthy arrived in Rodgers’s second season, and he recognized the talent that spent Sundays holding clipboards. Since 1993,
McCarthy has charted quarterbacks in five footwork drills that rate agility and movement. In his three backup seasons, Rodgers improved most in those areas, McCarthy said, to where he now ranks “at the top of all of them.”
In what McCarthy calls his Quarterback School, Rodgers concentrated on tuning his fine motor skills: hand-eye coordination, finger dexterity, mechanics. He also lowered where he held the ball for a smoother, more consistent motion.
By the end of Rodgers’s second year, McCarthy and Thompson saw him as a starter who happened not to start. With his quarterback coach,
Tom Clements, Rodgers studied every play from the Packers’ previous season. He also took the spring practice repetitions when Favre stayed home in Mississippi.
Between Rodgers’s second and third seasons, Quarterback School consisted of 10 hours in the film room and 3 hours on the practice field a week, an offensive study conducted in “painstaking detail,” Clements said.
Eventually, Rodgers focused less on learning the Packers’ offense and more on clarifying why defenses ran certain coverages, schemes or fronts. Now, when Rodgers drops back to pass, he does not look for his receivers. He looks for defenders, where they are, where they might move, what that means or could mean. Then he throws for receivers headed toward open space.
https://www.nytimes.com/2011/12/03/sports/football/the-education-of-the-packers-aaron-rodgers.html
