Could moneyball work in the NFL? Well first, what is moneyball? For one thing it's a movie staring Brad Pitt (It's also a book but I don't read so I don't care). The film and book were based on Billy Beane, a front office executive of the Oakland Athletics. The A's are a small market baseball team and so it's significantly more difficult for them to have success, given that a team like the Yankees can spend nearly 3 times as much on MLB players payroll then Oakland could.
So Beane got to work to find players who had a greater value than their general perception. One example is while most GM's would use batting average, Beane would instead use on base percentage, a stat that takes things like walks into account. Because at the end of the day as long as you're getting on base it doesn't really matter how you got there. So while a player hitting .240 with an on base percentage of .260 with 20 home runs might demand 8 million dollars, a similar player hitting .200 with an on base percentage of .260 and 20 home runs would only demand 2 million. So in signing the second guy you get the same value, but save 6 million dollars.
So could Moneyball work in the NFL? Well first you'd have to find some overvalued or undervalued statistics commonly used in front offices. One example of this is with kickers. Take a team like the Jets, they pretty much neglected the kicking position this past offseason, and it showed, as they had one of the worst field goal percentages in the NFL last year. They as a whole went 19/28 on field goals, and 23/27 on extra point attempts. Now lets compare that to Justin Tucker. While it's unfair to compare anything to Justin Tucker given how great he is, you'll see in a second why I'm bringing him up...
If you take Tuckers career kicking percentages for each distance (such as 20-29 or 30-39) and then look at how many attempts the Jets made from those distances in 2019, assuming Tucker had a typical year by his standards, he would've gone 24/28 and perfect on extra points. meaning he would've added 19 points to the Jets in 2019. Which means If Tucker was wearing a Jets uniform last season he would've added 1.1875 points per game, which using my own personnel stat "points added per 30 snaps", having Justin Tucker instead of what the New York jets had at the kicking position is about the same as having Jimmy Garoppolo over C.J. Beathard. In fact, it's a little better. But while Jimmy G is making 27,500,000 a year, Tucker is making just 5,000,000.
Now this is a bit misleading, because honestly the main goal as a GM when talking about the kicking position is to just avoid being a team that sucks at kicking. When it comes to field goal percentage, the difference between 1 and 16 is a lot closer than 17 and 32. But that being said one way to guarantee you don't suck at kicking would be to sign a top tier kicker to a 10 million dollar a year contract, and it would be a good move.
But that's honestly one example. NFL teams for the longest time wouldn't trade away a star player out of fear they wouldn't be able to replace them. But with teams like the Raiders and Dolphins trading Mack and Tunsil to get draft picks back, they're able to speed up their own rebuilding process. Bill Belichick for years has had success by instead of building a defensive line first, he would build a strong secondary, and trust that he can get pressure to the quarterback through scheme. He gave Stephon Gilmore 13 million a year, which at the time many called an overpay, but Gilmore just won defensive player of the year, and there's 46 NFL players who make more than him on defense alone.
You could even look at the Baltimore Ravens, Many passed on Lamar Jackson because they felt he could only play in a specific system. But John Harbaugh felt that a system with Jackson could result in a ton of success, and they were able to get him with a late 1st round pick. Patrick mahomes is another great example, as many wrote him off since he played in a college system that usually doesn't translate to the NFL, which allowed Kansas City to trade up to get him.
While some might argue that these aren't all moneyball decisions, remember what the definition of moneyball is. It's finding a player or tactic that is undervalued, and exploiting it. Even if it doesn't have anything to do with money it can still be moneyball. But there's one main problem with moneyball, Football is the most judgmental sport there is. Half of NFL head coaches/GMs are simply just trying to not get fired. Even though you statistically would score more points if you went for 2 every time, when Mike Tomlin did it in a regular season game against Dallas he was highly criticized. So if a less respected coach did that, it might cost them their job, despite it being the correct decision. The reality is, there's one more factor in pulling off moneyball. You have to have the balls to actually do it. Doug Peterson famously said that "conservative coaches go 8-8" and it's true. the fact they he constantly went for it on 4th down gave Philadelphia a huge edge in the 2017 season, which resulted in a Super Bowl victory. Anybody can come up with a good idea, but are you going to be the one to actually pay a kicker 10 million?