National Football League Players Association v. National Football League (Peterson)

NFL running back Adrian Peterson was suspended indefinitely and fined by the NFL commissioner after pleading no contest to reckless assault on his child, under a personal-conduct policy that lacked precise punishment terms but was clarified shortly before Peterson's plea by a commissioner's letter announcing enhanced discipline, including a six-week suspension, for domestic-violence offenses. The players' association (plaintiff) appealed to arbitration, arguing the letter was an impermissible retroactive new policy and that precedent bound the commissioner's discretion, but the arbitrator upheld the punishment, finding the commissioner had broad discretion and was not bound by precedent; the association then sought vacatur in federal court, the district court agreed the letter was an improperly retroactive new policy, and the NFL appealed.