The NFL players' union has sent a letter to former NFL commissioner Paul Tagliabue asking him to clarify several potential conflicts of interest when he hears the appeals of the New Orleans Saints' bounty case.

The NFLPA's concern stems from the fact that Tagliabue works for a law firm (Covington & Burling) that represents current NFL commissioner Roger Goodell in the defamation suit filed against him by Saints linebacker Jonathan Vilma.

Union Chief DeMaurice Smith suggested that Tagliabue be a witness during the appeals hearing rather than the arbitrator.

CBSsports.com first reported the story.