A few years back, my colleague Ben Morris wrote a piece for FiveThirtyEight called “Ndamukong Suh Is Cursed.” The basic premise was that huge contracts for non-quarterbacks in the NFL are usually doomed to failure, because of a couple factors: First, the team that “wins” the bid for a player is often the one who overpaid the most; beyond that, tying up a huge percentage of the team’s salary cap in one player can hamstring a roster even if the individual contract ends up providing fair value. Ben’s example of Suh, whose highly paid tenure with the Dolphins ended in March, wound up being a perfect case study — not only was the defensive tackle much less productive after the deal, but Miami also played worse after signing Suh.

That still hasn’t scared off teams from investing heavily in non-QBs, though. Last week alone, the record for defensive contracts was broken twice — first, when the L.A. Rams extended defensive end Aaron Donald for six years and $135 million; then, when the Chicago Bears traded for DE Khalil Mack and gave him a six-year, $141 million deal. In terms of guaranteed money (the only thing that really matters in NFL contract talk), each contract ensures the player an amount equal to about 50 percent of the current salary cap, a colossal number for any player, let alone one who doesn’t throw the ball. (The QB record is Matt Ryan’s 56 percent mark, set in May; the previous non-QB record of 45 percent had belonged to Broncos LB Von Miller from his 2016 deal.) So are teams still dooming themselves, or can these new deals possibly be worth it?

Generally speaking, it’s a bad idea for a team to tie up a bunch of guaranteed money in any single player, simply because it limits the rest of the team’s flexibility to build a competitive roster under the salary cap. This isn’t the NBA. Research shows that teams built on depth — rather than a few stars plus a bunch of scrubs — tend to do better, partly because injuries are inevitable in the NFL. Megadeals make deep teams harder to build. Maybe that’s why, according to data from ESPN’s Stats & Information Group, only three of the 16 players who signed a deal worth at least 40 percent of the current cap in guarantees since 2000 saw their team play better (in terms of its Simple Rating) over the following three seasons than it had in the three years prior. There’s a reason the Ravens and Seahawks were Super Bowl teams while paying Joe Flacco and Russell Wilson peanuts but haven’t had the same success once their QBs got paid.

The expectations for a player to produce after signing one of these huge guaranteed deals can escalate quickly. According to Stats & Info’s salary data and Pro-Football-Reference.com’s Approximate Value (AV) metric for estimating player value, a player needs to produce an extra point of AV in each of the next three years to justify every 6 additional percentage points in the ratio between his guaranteed money and the current cap. For Mack and Donald, that means needing to hit an average of about 13 AV per season over the next three years just to break even.

They’ve done it before — individually producing 15.2 AV per year since 2015 — but sustaining that level of performance is a tall order. Since 1960, there were 795 defensive players who, like Mack and Donald, produced between 35 and 55 points of AV over any given three-year span. Of those, just 116 (15 percent) reached the 13 AV average that Donald and Mack will need to break even over the next three seasons, and only 82 (10 percent) ended up matching their own established AV from the preceding three seasons. On average, this group of players lost 41 percent of its value from the previous three seasons to the next three years.

And merely breaking even on one of these contracts usually isn’t enough to help a team win, anyway. Since the NFL is a salary-capped league, paying players exactly what they’re worth will buy you an 8-8 record, all else being equal. The real value is in having players who outperform their salaries. We can see this in the relationship between big contracts and how they affected a team’s overall performance. Among established veterans who earned deals guaranteeing at least 30 percent of the current cap and met the three-year AV expectation implied by their contract, their teams still tended to decline by 1.2 points per game of Simple Rating on average over the following three seasons, with only 40 percent seeing their teams improve.

Just to reiterate: That was among the success stories, players who ultimately lived up to their contracts — in theory, the best-case scenarios for these kinds of deals. More often than not, though, it didn’t matter how well they played, because their salary figures made it hard to build up the rest of the roster. Quarterbacks can make up for this some by the fact that even top-tier QB deals are still probably paying them less than their true value. But for non-QBs such as Mack and Donald, it becomes very difficult to win championships while pulling in a guarantee worth nearly 50 percent of a whole season’s salary cap.

There are exceptions, of course: As part of their plan to build from the trenches, Philadelphia won it all last season with DT Fletcher Cox playing on a deal that guaranteed him 41 percent of the cap. Kansas City has also been competitive during LB Justin Houston’s 37 percent deal. And if you look back even further in history, as Ben did in his story, Reggie White and Deion Sanders were unqualified triumphs for big-ticket defensive free agency early in the salary-cap era. It’s possible the Bears and Rams can capitalize on their relatively cheap quarterback situations (with young signal-callers Mitch Trubisky and Jared Goff, respectively) to leverage Mack and Donald’s defensive production into boatloads of wins, too.

But it is perhaps telling that, in ESPN’s data (since 2000), the five-time champion New England Patriots have only guaranteed one player more than 25 percent of the cap in any contract they’ve signed: quarterback Tom Brady, who maxed out in 2013 with a deal paying him 46 percent of the cap. (Next-highest behind Brady is guard Logan Mankins, who was guaranteed 25 percent of the cap for the deal he signed in 2011; cornerback Stephon Gilmore inked the Pats’ most expensive defensive contract at 24 percent in 2017.) The Patriots understand fungibility better than maybe any other franchise in pro sports, and they do not commit huge sums of cash to anybody other than arguably the greatest quarterback in history.

Still, their rivals are trying to create a new paradigm. As my ESPN colleague Lindsey Thiry pointed out after Los Angeles inked Donald’s extension, the Rams have now committed nearly $239 million in guaranteed money since the 2018 league calendar began — and none of that was to Goff. As a result, their window to win a Super Bowl might be open for only two seasons before they have to start shedding talent to stay under the cap. Obviously, if L.A. ends up winning a ring anyway, it would lend plenty of validation to the strategy, perhaps spawning copycat paydays for defensive anchors. But until then, history says these deals usually just make championships harder to come by.