Back in 1960 -- not long before the start of the Super Bowl era -- Hall of Fame quarterback Johnny Unitas threw for 3,099 yards, marking the first time in NFL history a player cleared 3,000 yards in a single season.
Roughly 60 years later, we could soon see a quarterback double that mark.
As we enter the 2021 NFL season, 5,477 stands as the NFL single-season passing record, set in 2013 by a 37-year-old fellow named Peyton Williams Manning with the Denver Broncos.
Now that the league has added a 17th game, that record is in immediate jeopardy, and a previously unreachable target of 6,000 yards isn't out of the question.
"There's no doubt that that can happen," said former Miami Dolphins quarterback Dan Marino, the first to throw for 5,000 yards. "Guys are throwing for, what 5,300 yards? Two more games, you have a great year, you have a great time, you got players that are playing at a high level. That definitely can happen.
"If I was still younger with [receivers Mark] Duper and [Mark] Clayton, I would guarantee you 6,000. But I don't have to do it now. I don't have to prove it."
After Unitas hit 3,000, it took fellow Hall of Famer Joe Namath less than a decade to reach the next plateau, with 4,007 passing yards for the New York Jets in 1967. Then it was Marino with 5,084 yards in 1984. It took another 28 years before Drew Brees became the second to reach 5K. Overall, eight different quarterbacks have reached 5,000 -- with Brees doing it five times.
Manning appeared in all 16 of Denver's games during that 2013 season (he played 96% of the offensive snaps), which means he averaged 342.3 passing yards per game. Extrapolated over 17 games, that total jumps to 5,819 yards, which tells us it's not ridiculous to think a quarterback can reach 6,000 yards in the modern NFL.
"It can happen," said Kansas City Chiefs quarterback Patrick Mahomes. "You never know until you go out there and play."
Here is what a path to 6,000 passing yards looks like, as well as the most likely candidates to hit the mark in 2021.