The National Football League’s regular season will end on Sunday night with a nationally televised entry of the roughly four-decade-old rivalry between the Washington Redskins and the Dallas Cowboys. George Allen, the Redskins coach who presided over seven consecutive winning seasons after he arrived in Washington, in 1971, essentially invented this feud as a rallying device for the sorry franchise that he had inherited, and the N.F.L. has profited from it ever since. Allen was a showman and a motivational speaker. Once, he karate chopped some boards to demonstrate how he intended to beat up Tom Landry, the staid and awesomely successful Cowboys coach, who posted twenty consecutive winning seasons after 1966. Allen also donned an Indian headdress and whooped about the Cowboys.

That set a standard of poor taste that has been upheld ably by the current guardians of the rivalry, Dan Snyder and Jerry Jones, two interfering team owners with mountainous egos and corner-cutting management styles—they were both recently fined for violating N.F.L. salary rules that they’d helped to write. And yet, both have fielded decent, if not great, teams this year, with young players—Robert Griffin III, Dez Bryant—who are dazzling to watch. Expect huge television audiences.

There is pageantry within the N.F.L.—excess, shamelessness, rawness, and a struggle for control by League overseers in the face of many tendencies toward anarchy—that has made the League more successful than any other American professional sport. At the same time, it is more imperilled. This has been a season of sold-out stadiums and high cable ratings. But it may also be remembered as the beginning of the end—the season in which the League’s balance sheet of accumulating liabilities became fully apparent.

The best on-field story this weekend will take place in Indianapolis, where the Colts head coach Chuck Pagano returns after a three-month leave that he required to seek treatment for leukemia. In November, Pagano’s doctors announced that his disease was in remission. He is coming back for a final regular-season home game against the Houston Texans that doesn’t mean much to the Colts—they are already in the playoffs, as a wild-card entry, behind the rookie quarterback Andrew Luck’s four thousand yards and twenty-one touchdown passes.

Luck and R.G. III were drafted number one and two over-all last April, and while Griffin has had a better year statistically (mostly because he has thrown fewer interceptions) Luck has set a rookie record for leading the most come-from-behind victories. He hasn’t gotten as much ink or airtime as he deserves. The Colts won two games last year; their turnaround has been a triumph for Jim Irsay, the Grateful Dead obsessive and second-generation multi-millionaire who owns the team.

Irsay made an unpopular decision in the off-season to cut loose Peyton Manning and draft Luck. Manning seems driven to win a Super Bowl for Denver to prove Irsay wrong, and he may succeed. But Irsay seems mellow; a couple of days ago, he announced that he would place his collection of rock-and-roll memorabilia, including Tiger, a guitar played by Jerry Garcia that he bought a decade ago for just under a million bucks, on display at the Indiana State Museum under the title “Chaos Is a Friend of Mine: Cultural Icons from the Jim Irsay Collection.”

The Colts could become the first N.F.L. team to petition for the locker-room use of medical marijuana.

There are, however, two far larger challenges facing Roger Goodell, the N.F.L. commissioner, that could presage a long-term decline. They are the same two that brought professional boxing down from its heights of popularity and economic power during the mid-twentieth century: corruption and concussions.

The bounty scandal involving the New Orleans Saints, which broke last March, has retreated from the news, but it remains the most serious instance of corruption in N.F.L. history since 1963, when the Green Bay Packers running back Paul Hornung and the Detroit Lions defensive tackle Alex Karras were suspended for a season for betting on games and hanging out with professional gamblers. The Saints’ case involves a system for pooling funds to pay players to target opposing quarterbacks and others for injuries.

Earlier this month, the Associated Press obtained transcripts of interviews that several current and former Saints coaches gave to N.F.L. investigators about how the system worked. Two former assistant coaches—Gregg Williams and Mike Cerullo—described Joe Vitt, the current interim head coach of the Saints, as an instigator of the pay-to-injure plans. Vitt denied their accounts and said that Williams and Cerullo were disgruntled former employees with axes to grind. It matters who is right, because if Williams and Cerullo spoke accurately, the N.F.L. has endemic problems.

According to the transcripts, Williams said that he had tried to end the bounty program, but that Vitt overruled him and issued an obscenity-laced speech in which he declared that Roger Goodell was not going to tell the Saints to “stop doing what won us the Super Bowl. This has been going on in the National Football League forever, and it will go on here forever, [and] when they run [me] out of there, it will still go on.”

Paying Saints players to injure opponents may have been more of a motivational game than an economic system—it’s not clear yet how much money really changed hands, or whether the amounts were significant enough to be more than symbolic. Yet if pay-to-hurt is as endemic as Vitt reportedly suggested, it may eventually lead to game-fixing schemes by professional gamblers. At least a quarter of a billion dollars is wagered weekly on N.F.L. regular-season games. Big dollars, weak refereeing, and corrupted locker rooms are a recipe for organized crime.

Then there is the most startling number of this N.F.L. season: four thousand. Yes, that is roughly the number of yards Andrew Luck threw for in his rookie Colts season. But it is also approximately the number of former N.F.L. players who have now joined civil lawsuits against the League, seeking damages over the League’s failure to protect players from concussions, according to Judy Battista of the Times. That is more than the entire League-wide roster of active players in any single season.

So far, Goodell and the owners have responded to the concussion problem in a way that is familiar from the N.F.L.’s past handling of existential threats: litigation, delay, denial, and inadequate, incremental fixes, all constructed to outlast and outflank opponents.

That strategy helped the N.F.L. overcome antitrust allegations, but it won’t work in the concussion litigation. If Goodell and the owners don’t change the League’s rules fast enough to reduce concussions to a level comparable to that present in baseball and basketball—where concussions are very rare accidents—then the League will face a devastating reckoning. The tobacco and asbestos industries’ experiences show that, in the long run, if a commercial product causes widespread injuries among customers or workers, the manufacturer will pay—and government regulators may step in even before courtroom verdicts are fully calculated.

The problem can be fixed; concussions are not as fundamental to football as they are to boxing. But eliminating kickoffs and encouraging players to tackle lower, avoiding each other’s heads—measures Goodell has started to implement or has hinted that he might take up—are not going to get it done. As in rugby, N.F.L. tackling will have to evolve among players into an act of mutual, subtly agreed stoppage in play, when one player gets his arms adequately around another—not the act of all-out assault by one player against another that it is now.

It will take years, and vision and courage on the part of N.F.L. owners, to successfully shape such a change. The owners would have to set aside large sums to settle lawsuits over past injuries and make adequate provisions for future player health and economic security, all while maintaining a degree of speed and excitement on the field that would generate the sorts of huge TV ratings the League will enjoy on Sunday night. Do the likes of Dan Snyder, Jerry Jones, and Jim Irsay have that sort of vision? Chaos is not a friend of theirs, yet amid wealth and self-indulgence, they seem to prefer it.

Photograph by John McDonnell/Washington Post/Getty.