Quarterback Deshaun Watson was suspended Monday for six games for violating the N.F.L.’s personal conduct policy and was not fined, concluding the league’s 15-month investigation into sexual misconduct claims made against him by more than two dozen women.

It was the first N.F.L. player disciplinary decision to be handled by an arbitration process established in the 2020 collective bargaining agreement, which sought to bolster a system that had been criticized for inconsistencies and potential conflicts of interest.

Since Roger Goodell became N.F.L. commissioner in 2006, he has taken a stricter stance on player punishment than his predecessors, levying some of the lengthiest player suspensions in the league’s history. The personal conduct policy includes provisions for penalizing players even if their transgressions did not result in criminal convictions.

But while Goodell once wielded unilateral power in disciplinary action, revisions to the policy in the last decade have shifted some of the process to third parties. Watson’s penalty was imposed by a retired federal judge who was jointly approved by the league and the players’ union. But Goodell, or someone he appoints, would still have the last word if the league appeals the decision.

Here are some of the most notable suspensions of N.F.L. players during Goodell’s tenure as commissioner:

Michael Vick. Vick, a former Atlanta quarterback, was indefinitely suspended in 2007 for his role in a dogfighting scandal. The suspension lasted two seasons; Vick was reinstated before the 2009 season after serving an 18-month prison sentence.

Aldon Smith. Smith, a defensive end who played for San Francisco and Oakland, was suspended in 2015 for a violation of the substance abuse policy (he had been charged with drunken driving). The suspension lasted until Smith was signed by Dallas in 2020 and reinstated.

Dominic Rhodes. Rhodes, a running back who played for several teams, was suspended indefinitely in 2011 after failing a third drug test. He was reinstated in 2014.

Jerrell Freeman. Freeman, a linebacker, was suspended twice for multiple games after positive tests for performance-enhancing drugs while with Chicago in 2016 and 2017. The N.F.L. suspended him for two years for another failed test in 2018, though he announced his retirement days before the suspension.

Adam (Pacman) Jones. Jones, a cornerback then with Tennessee, was suspended for the 2007 season after multiple arrests, including for his role in a fight at a strip club that led to three people being shot.

Calvin Ridley. Ridley, an Atlanta receiver, was suspended for at least a year after he bet on N.F.L. games while away from the team during the 2021 season.

Donte’ Stallworth. After striking and killing a pedestrian in Miami Beach while driving drunk, Stallworth, then a receiver with Cleveland, was suspended for the entire 2009 season. He pleaded guilty to manslaughter.

Darren Waller. In 2017, Waller, then a Baltimore tight end, was suspended for at least one year for violating the substance abuse policy. He had been suspended for four games in the 2016 season for the same violation. He was reinstated in 2018.

Martavis Bryant. Bryant, a receiver, was suspended for at least one year for violating the league’s substance abuse policy in 2016. After being conditionally reinstated in April 2017, Bryant was suspended indefinitely in 2018 for violating the terms of the reinstatement.

Travis Henry. In 2008, Henry, then a Denver running back, was suspended for at least one year after he tested positive for marijuana for the third time. Before his suspension was complete, Henry was sentenced to three years in prison for financing a drug operation. The N.F.L. reinstated him in 2012.

Josh Gordon. Gordon, a receiver currently with Kansas City, has been suspended six times for violating the league’s substance abuse policy, including a suspension for the entire 2015 season. He was most recently suspended in January 2021 and reinstated in September 2021.

Ray Rice. Rice was initially suspended for two games by the N.F.L. after his arrest on domestic violence charges in July 2014. Two months later, after TMZ released a more graphic video of the assault that showed Rice knocking his fiancée unconscious in a hotel elevator, Baltimore released the running back and he was suspended indefinitely by the N.F.L. Rice was reinstated on Nov. 28, after the first 12 weeks of the 2014 season, but he was never signed by a team.

Vontaze Burfict. Burfict, an Oakland linebacker, was suspended for the remainder of the 2019 season after his helmet-to-helmet hit to Indianapolis tight end Jack Doyle in a Week 4 game. Burfict’s penalty, the N.F.L.’s longest suspension ever for on-field actions, took into account his lengthy history of violations of the league’s player safety policies.

Josh Brent: For his role in the 2013 drunken driving death of a Dallas teammate, Brent, a defensive tackle, was suspended for 10 games of the 2014 season. He was also sentenced to 180 days in jail and 10 years of probation.

Antonio Brown. In 2020, the league suspended Brown, a receiver who was a free agent at the time, for sending threatening texts to a woman who accused him of sexual misconduct, and for his role in a dispute with a moving company employee. He pleaded no contest to burglary and battery charges and received two years of probation. Brown denied the sexual misconduct claim.

Chris Henry. The league suspended Henry, a Cincinnati receiver, in 2007 after he was arrested four times between December 2005 and June 2006.

Terry (Tank) Johnson. Johnson, a defensive tackle then with Chicago, was suspended in 2007 after the police raided his home and found six unregistered firearms, a violation of his probation on an earlier gun charge.

Mychal Kendricks. Kendricks was suspended after pleading guilty to two insider trading charges in 2018.

Josh Brown. Brown, a kicker who had been suspended for one game in 2016 after admitting to the Giants that he abused his wife, was suspended for six more games in 2017 after documents released by the Washington State Police revealed he had written extensively about the abuse.

Adrian Peterson. After being indicted on child abuse charges, Peterson, then Minnesota’s star running back, was suspended for the remainder of the 2014 season, which resulted in six missed games.

Myles Garrett. The N.F.L. indefinitely suspended Garrett, a Cleveland defensive end, after he removed the helmet of Pittsburgh quarterback Mason Rudolph and hit him with it in 2019. The league reinstated Garrett two days after he met with Goodell and league representatives at the end of the season.

DeAndre Hopkins. Hopkins, an Arizona receiver, was suspended in May after violating the league’s performance-enhancing drug policy.

Ezekiel Elliott. Elliott, a star running back for Dallas, was suspended in 2017 after a league investigation into domestic violence allegations. An ex-girlfriend accused him of assaulting her five times in Columbus, Ohio, where he played at Ohio State. He was never criminally charged.

Albert Haynesworth. In 2006, Haynesworth, then a Tennessee defensive tackle, was suspended for stomping on the head of an opposing player. Goodell handed down the suspension weeks after he became commissioner.

Terrelle Pryor. Pryor, who had been handed a five-game suspension by the N.C.A.A. for accepting improper benefits while at Ohio State, entered the N.F.L. supplemental draft instead. The N.F.L. mandated that he sit out the first five games of his rookie season.

Tom Brady. Brady was suspended in 2016 for his involvement in the Deflategate scandal that emerged after Indianapolis accused New England of deflating footballs to give Brady an advantage.

Ben Roethlisberger. Roethlisberger was initially handed a six-game suspension in 2010 after being accused of sexually assaulting a woman in a Georgia bar. He was not criminally charged and Goodell reduced the suspension to four games after an appeal. The Pittsburgh quarterback was the first player to be suspended under the league’s personal conduct policy without having been charged with a crime.

Greg Hardy. The N.F.L. suspended Hardy, a defensive end, for 10 games in 2015 for his role in a domestic-violence case. An arbitrator reduced the penalty to four games.

Ikemefuna Enemkpali. The league suspended Enemkpali, then a Jets linebacker, for punching his own team’s quarterback Geno Smith during a locker room altercation in 2014.

Jameis Winston. Winston, a quarterback then with Tampa Bay, was suspended for the first three games of the 2018 season. The penalty stemmed from an N.F.L. investigation into a BuzzFeed report that said he made an unwanted sexual advance on an Uber driver in March 2016.