It is a key NFL matchup: Saints linebacker Jonathan Vilma, suspended for the 2012 season because of his alleged involvement in Bountygate, is suing commissioner Roger Goodell for defamation. The argument is straightforward: that Goodell defamed Vilma by wrongly naming him in the bounty report. In the report Goodell alleged that "defensive captain Jonathan Vilma offered $10,000 in cash to any player who knocked [Brett] Favre out of the game." Vilma denies any bounty involvement.
The NFL will try to have the case dismissed, arguing that the lawsuit is frivolous. The league will also assert that the suit is preempted by contractual and collectively bargained language that gives the commissioner final say on player discipline; and that by virtue of his contract and NFLPA membership, Vilma consents to Goodell's sweeping authority; and thus no judge should hear the grievances. If a court does agree to hear the claim, the NFL will probably petition for the case to be moved from Louisiana—probably to New York, where the league is headquartered.
The NFL likely worries that if a judge orders pretrial discovery, the league would have to reveal its informants, which could undermine the NFL's investigation and provoke other suspended players and coaches to challenge the commissioner. Keep in mind, informants talking to league investigators are not under oath, and can lie—including to protect themselves—without legal repercussion.
The NFL may also be leery of settling the suit in any way that reduces Vilma's suspension. If Goodell lowers penalties for a player who sues him, expect other players to do the same. In short, this case is a threat to sports' most powerful commissioner.