The NFL, which has built a multi-billion dollar empire out of its violent and quintessentially American game, is under attack as never before over its handling of off-field violence involving players.
Health concerns facing players, wrangles over drug testing and even charges of racism have failed to dent the league's popularity.
But charges of violence by players against women and children - and a clumsy response by the league and individual teams - have fans and sponsors on edge as the 2014 season moves into its third week.
Commissioner Roger Goodell has come in for particular criticism over his handling of Ray Rice, the running back who helped the Baltimore Ravens to a Super Bowl title after the 2012 season.
Goodell initially banned Rice for two games over a February incident in a casino elevator in which Rice knocked his then-fiancee Janay Palmer unconscious.
After a video of the actual punch was posted online in August, Rice was promptly cut by the Ravens and banned from the league indefinitely by Goodell - a punishment the player's union is appealing.
The case is made murkier by a report that Goodell or others in the league office knew of the video before issuing the two-game ban that was widely derided by domestic violence advocates.
The Rice case sparked a "#Goodellmustgo" campaign on social media, but the commissioner who has presided over continued growth of the league's formidable fortunes continues to enjoy the support of team owners.
Forbes magazine estimated in August that the average worth of the 32 NFL teams is 1.43 billion - the highest in 17 years.
The Dallas Cowboys top that list at an estimated worth of $3.2 billion - tied for second most valuable sports franchise in the world with Spanish football powerhouse Barcelona behind Real Madrid ($3.4 billion).
The league stands to reap some $5.1 billion in media rights revenues alone this season, its sensational viewership ratings making it a merchandising juggernaut and a mouth-watering partner to any number of corporations.
So far sponsors are standing by the league, although some top partners, including hotel chain Marriott, brewer Anheuser-Busch and beverage giant PepsiCo have issued statements expressing concern.
The furor over Rice was followed by similar yo-yoing in the cases of Carolina Panthers defensive end Greg Hardy - convicted of assaulting a former girlfriend and threatening to kill her - and Minnesota Vikings running back Adrian Peterson - charged with child abuse in Texas after a whipping he administered to his four-year-old son.
Hardy played the first game of the season for the Panthers after launching an appeal of his conviction.
The Vikings had planned to welcome Peterson back to action after he missed one game.
But amid a growing public uproar, both teams negotiated deals with their players to place them on paid leave as their legal cases proceed.
David Carter, a principal of the Sports Business Group and executive director of the University of Southern California's Marshall Sports Business Institute, said the league will have to prove to sponsors, as well as fans, that they can address such issues more effectively.
"They routinely also want to conduct business with organizations that reflect their values, as well as the values of their shareholders and customers," he said.
"If sponsors believe that the NFL will ultimately and satisfactorily address this crisis they will remain behind the league. However, if they view the NFL to have a chronic problem, they may redirect their spending."
GOODELL UNDER FIRE
Goodell continues to draw criticism for his low profile as the Peterson case exploded, but he has moved to try to bolster the league's policies in dealing with players accused of domestic violence.
Former FBI director Robert Mueller will lead an independent investigation into the NFL's handling of the Rice case, and Goodell announced the hiring of three domestic violence experts as senior advisers to the league.
Real policy changes, however, will require cooperation from the players' union, which is appealing Rice's suspension "to protect the due process rights of all NFL players." "Sponsors, and all those that conduct business with the NFL, must realize that although the league may want to act unilaterally, the NFL Players' Association may have a different outlook," Carter noted. "So, the NFL may want to be proactive in terms of major changes dealing with player misconduct, but they will have to work with the union to get this done."