GREEN BAY, Wis. -- They used to line up garbage cans -- the 50-gallon-sized receptacles -- on the goal line, and let their quarterbacks take aim.
So McCarthy and Packers equipment manager Red Batty came up with something better: A net attached to a metal ring positioned at a 60-degree angle and raised approximately 6 feet off the ground.
Come to a training camp practice, and you'll likely see Rodgers bury a ball in the bottom of the net from some 50 yards away.
"We felt like we needed to throw it with more of an arc," McCarthy said, explaining why he wanted something more than garbage cans.
When Rodgers came into the NFL, he knew he had the arm to throw it deep. But he admitted he had much to learn about the deep ball.
"You really need to work on that touch," Rodgers said.
"Is there anyone better?" Packers receivers coach Edgar Bennett said. "I don't think so."
Since Rodgers became the Packers' starter in 2008, no one has thrown more touchdown passes on deep balls that traveled 35 yards or more in the air, according to ESPN Stats & Information. He has 21 of them, tied with Drew Brees. And Rodgers' completion percentage of 39.2 percent on such passes is the best in the league in that span.
Rodgers finished the 2014 season with a league-best seven touchdowns on passes that went 30 or more yards in the air, and he posted a league-best Total QBR of 100.0 on such throws, completing 10-of-19 for 561 yards without an interception.
But for Rodgers and his coaches, it's not about the numbers. It's about what they see -- or don't see -- on the film. Spend any time with Rodgers, McCarthy and quarterbacks coach Alex Van Pelt, and you'll hear them talk about a deep ball that goes "off the screen" when they're watching it on tape. It's something they learned at the University of Pittsburgh from coach Paul Hackett back in the early 1990s.
"Sometimes there's different angles -- I can remember the old Beta-cam video -- but when the ball went out of the screen, it was always at the right angle coming in," McCarthy said.
Which goes back to those nets that Batty's equipment staff wheels onto the practice field.
"That's a Paul Hackett, Coach McCarthy thing," Van Pelt said. "They would always say, 'Ah, it didn't leave the screen; it's going to be too flat.' The trajectory of the throw makes the angles tougher for the defensive back. So if it's a flat ball, he's got a better chance of breaking it up. If it's down the chimney, he's got less chance of breaking it up. If it leaves the screen, then it's got a better chance of coming down the chimney."
Just like the 64-yarder Rodgers completed to Jordy Nelson in Week 11 this season against the Philadelphia Eagles at Lambeau Field did. Ask Van Pelt about that play by saying that ball looked like it … and he will finish the sentence.
"... Fell out of the sky?" Van Pelt said. "That's a good deep ball. That's what we’re looking for."
More often than not, Nelson is the target of Rodgers' deep balls. He caught three touchdowns of 65 yards or more this season, and he has four career touchdown catches of 80-plus yards.
"Aaron does such a good job, especially on our double-move deep balls, that you have time to adjust," Nelson said. "It's hard to throw it on a line and know exactly to hit it at 57 yards or whatever. But if you put air under it, if it's a little short or long, you can gauge your speed to it."
From Rodgers' perspective, however, it's not just chuck and duck. There's a precision to it. In his mind's eye, he sees a spot that he calls "The Red Line," a mark between the sideline and the painted numbers on the field that serves as an aiming point.
"From the filming angle if the ball goes out of the screen, you can complete it in the 42- to 44-yard range," Rodgers said.
Nothing but net.
Read more: As Rodgers chases his second career Super Bowl, he has one title firmly in his grasp: the NFL's best deep-ball thrower. Take a look at how Rodgers practices his long ball.