(CNN) -- The New Orleans Saints' defense had a bounty program that paid players for injuring opponents and for making interceptions and fumble recoveries, the National Football League said Friday.
The program involved as many as 27 defensive players, at least one assistant coach, and was active during the 2009, 2010 and 2011 seasons, said the league.
"The payments here are particularly troubling because they involved not just payments for 'performance,' but also for injuring opposing players," NFL Commissioner Roger Goodell said in a statement.
"It is our responsibility to protect player safety and the integrity of our game, and this type of conduct will not be tolerated. We have made significant progress in changing the culture with respect to player safety and we are not going to relent," he added.
Goodell has received the results of an NFL investigation into the Saints' program and will decide on discipline, which could include fines, suspensions and forfeiture of draft choices, the NFL said.
Saints owner Tom Benson released a statement acknowledging the probe and calling its results "troubling."
"I have offered and the NFL has received our full cooperation in their investigation. While the findings may be troubling, we look forward to putting this behind us and winning more championships in the future for our fans," he said.
According to the NFL, Saints players regularly contributed cash to a pool, the total of which may have been as high as $50,000 or more at its peak. They were paid $1,500 for a "knockout," when an opposing player was not able to return to the game, and $1,000 for a "cart-off," when an opposing player had to be carried off the field. In some cases, particular players on the opposing team were targeted, the NFL said.
The program was administered by then-defensive coordinator Gregg Williams, with knowledge of other coaches, said the league. Head coach Sean Payton did not directly participate, nor was he involved in the administration of the program, however, he knew about the allegations and failed to stop it, the NFL said.
Williams, who is now defensive coordinator for the St. Louis Rams, released a statement on the allegations, the New Orleans Times-Picayune reported Friday.
"It was a terrible mistake, and we knew it was wrong while we were doing it. Instead of getting caught up in it, I should have stopped it. I take full responsibility for my role. I am truly sorry. I have learned a hard lesson and I guarantee that I will never participate in or allow this kind of activity to happen again," the newspaper quoted him saying.
Saints players were also allegedly paid for interceptions and fumble recoveries. Payouts doubled and tripled during the playoffs, the NFL said. The New Orleans Saints won the Super Bowl after the 2009 season.
"There is no question that a bounty program violates long-standing league rules. Payments of this type -- even for legitimate plays such as interceptions or fumble recoveries -- are forbidden because they are inconsistent with the Collective Bargaining Agreement and well-accepted rules relating to NFL player contracts," said the league.
It informed the NFL Players Association about the Saints' investigation earlier Friday. The NFLPA said it would review the information and stressed that health and safety issues are "paramount."
The NFL has been under fire of late as hundreds of former players and their families are currently suing the league for alleged negligence, claiming that it didn't do enough to mitigate the risks despite what many say is an inherently dangerous sport.
An attorney for former Philadelphia Eagles fullback Kevin Turner, Stephen F. Rosenthal -- whose Miami-based firm represents 137 other players and their families who've filed a class-action suit against the league -- said Turner has likely suffered from undiagnosed concussions. He accused the league of deliberately withholding information deemed critical to player safety.
Stars such as former quarterback Jim McMahon, as well as running backs Jamal Lewis and Dorsey Levens, have filed similar lawsuits in states across the country.
Attorneys representing Lewis and Levens accuse the league of having used a "hand-picked committee of physicians" to misrepresent evidence of the effects of head trauma, particularly concussions.
The league denies the claims and released a statement saying it "has long made player safety a priority and continues to take steps to protect players and to advance the science and medical understanding of the management and treatment of concussions."
"The NFL has never misled players with respect to the risks associated with playing football," the statement added. "Any suggestion to the contrary has no merit."
The league has in recent years also made strides to strengthen rules that govern on-the-field conduct, while adding sideline medical staff -- unaffiliated with the teams -- to more independently evaluate injured players.
In 2005, the league banned the practice of tackling a player by using his shoulder pads, a move commonly referred to as a "horse-collar" tackle, after concluding it commonly resulted in injury.
It also strengthened a 1979 rule prohibiting players from using their helmets to butt, or "spear" players during a tackle -- a rule that critics often complained had lacked enforcement.