Union sues NFL challenging Peterson ruling

[ESPN]

The NFL Players Association has filed a lawsuit against the NFL in U.S. District Court in Minneapolis, challenging an arbitrator's decision made Friday to uphold Adrian Peterson's suspension by the league.

http://espn.go.com/nfl/story/_/id/12031568/nfl-players-association-sues-nfl-ruling-case-adrian-peterson-minnesota-vikings