Great NFL franchises pay excellent players fair-market salaries (or less) to help them win championships. Not-so-great NFL franchises pay ordinary players premium salaries to help them stay competitive.

The weakest NFL franchises pay their former players top dollar to play for other teams. And even recently-successful franchises have fallen into that trap.

In the latest of these "dead money" episodes, the Dolphins traded longtime starting quarterback Ryan Tannehill and a future draft pick to the Titans last week for a pair of draft picks. The trade leaves the Dolphins on the hook for $18.4 million that cannot be used to improve the roster this season.

For those of you who don't eat, drink and breathe NFL salary-cap economics, "dead money" is leftover, prorated signing-bonus money—left over after a player is traded or released.

Sign a player to a four-year contract with a $20 million signing bonus, and that bonus is spread out at $5 million per year for cap-accounting purposes. If the player is released after one year, the team is still responsible for the remaining three years—$15 million—in cap space (even if all the actual money has been paid out).

Tannehill's $18.4 million joins the $13.1 million in dead money the Dolphins were already choking down for Ndamukong Suh, who played for the Rams last year. The cap hit from Suh's mega-contract was so huge that the Dolphins elected to spread it across two years to soften the blow.

Throw in some smaller sums, and the Dolphins will eat $36.4 million in dead money in 2019. (All cap figures courtesy OverTheCap.com.) With the current salary cap at around $188 million, that means nearly 20 percent of their available cap space will be allotted to players who are no longer with the team.

At least Miami is confronting its problem. The team is doing its penance for bad contracts of the past. The new Dolphins braintrust is "rebuilding," or less diplomatically, stinking on purpose for at least a year. Their current cap situation is less a symptom of an illness than a sign that the cure is starting to work.

But while the Dolphins now are dealing with their problem deliberately and tactically, other teams have been causing problems for themselves instead of solving them.

As you probably heard, the Steelers and Giants traded away superstar wide receivers Antonio Brown and Odell Beckham Jr. to the Raiders and Browns earlier this month. The Steelers will absorb a $21.1 million cap hit for the right to not employ one of the NFL's best players. The Giants will swallow $16 million in the latest act of flagrant self-sabotage.

Both Brown and Beckham are labeled as "headaches," of course, and it's easy to spin their trades as efforts to "change the culture." Whatever you may think of high-maintenance wide receivers like Brown and Beckham, it's clear that the shrewd financial move would be to trade them and their allegedly toxic attitudes before (or instead of) handing them massive prorated signing bonuses. 

Some NFL analysts claim that the salary cap is meaningless because shrewd organizations can manipulate the numbers a hundred different ways: Contracts are loaded with phony non-guaranteed years, players are asked to restructure existing deals, and so forth. But there are real consequences for sacrificing cap space to sunken costs.

The $21.1 million in cap space the Steelers are wasting on the Good Riddance Antonio Brown Fund could have been better used many ways, from more aggressive free-agent pursuits (acquisitions like Steven Nelson, Donte Moncrief and Mark Barron aren't going to make the Steelers Super Bowl contenders again) to upfront money in Ben Roethlisberger's pending contract extension.

The Jaguars are swallowing $24.1 million in 2019 ($16.5 million of it is what they inexplicably guaranteed to Blake Bortles last year) while trying to quickly return to the playoffs with Nick Foles at quarterback.

The Jaguars don't have much of an offensive supporting cast for Foles, and they cannot overspend elsewhere because a Jalen Ramsey extension is looming. So they were forced to load up on affordable receivers (Chris Conley, tight end Geoff Swaim) and pass protectors (former Bengals left tackle disaster Cedric Ogbuehi) instead of pursuing the best free agents.

The Jaguars, like the Steelers, are hoping to reach the playoffs with the money to pay a much-needed extra marquee starter or two tied behind their backs.

So dead money isn't some meaningless paper loss. It functions in about the same way interest debt impacts your personal finances:

• The Dolphins are the team that's moving in with their parents for a year or two while they pay down their student loans.
• The Steelers and Jaguars now owe hundreds per month on the speedboat they crashed into that vacation property they bought. They can still go out for dinner-and-drinks on Friday and Saturday nights, but they are in deep trouble if the roof starts leaking.
• And the Giants? Long infomercials on daytime television are aimed at folks who handle their money like the Giants, who are now eating $33.7 million in dead money this season for Beckham, Olivier Vernon, Damon Harrison and others after sacrificing tens of millions of dead-money dollars on Jason Pierre-Paul and others last year.

It's easy to laugh at the Giants as they try to keep their ship from sinking by throwing the life preservers overboard. Yet the Steelers, with their aging roster and increasingly dubious approach to player management, could be in the same predicament in a few years if Roethlisberger's play slips after he signs a bonus-heavy extension.

The Dolphins hope taking a mega-dose of their dead-money medicine in one year will cure them, but it's not quite that easy. Even the Browns, the poster-children for successful Moneyball-flavored credit repair, are now eating $18.9 million in dead money to pay for players (Jamie Collins, Kevin Zeitler, Jabril Peppers, Carlos Hyde, Corey Coleman) they once hoped would be part of the solution.

Dead money represents double jeopardy: a lost player (or players) and a lost opportunity to get another player (or players). It can force a rebuilding team to wander in the wilderness for years and trap a would-be contender in a loop of diminishing returns. 

The best course of action is to avoid dead-money situations before they arise: Avoid back-loaded contracts with big bonuses, don't overpay for mediocre stability (especially at quarterback), learn to talk to your touchy wide receiver instead of talking at him.

And when a dead-money hit becomes inevitable, smart organizations put it off until long after the Super Bowl window closes.

The Saints recently restructured Drew Brees' contract for the umpteenth time, creating a potential dead-money hit of $21.3 million for the 2020 season. Brees' current salary for 2020 is $0.00, meaning that the Saints will have to renegotiate if he plays beyond this season. No matter how much cap finagling both parties do, the Saints will someday be forced to invest so much cap space in Brees that they'll be forced practically to field a roster made up entirely of rookies and contest winners.

When that happens, the Saints will at least have memories of the Super Bowl (or Super Bowls) Brees helped them win, plus the many times they came close.

All most teams get in exchange for all the dead money on their budgets is a bad taste in their mouths.