Minnesota Vikings running back Adrian Peterson may be one step closer to playing in the NFL again after a judge ruled against his suspension on Thursday. Peterson was banished after a child abuse charge in September and was suspended until at least April 15. The NFL said it has appealed the decision.

U.S. District Judge David Doty said the league exceeded its authority to punish Peterson and arbitrator Harold Henderson “simply disregarded the law of the shop.” Peterson won’t be immediately reinstated—the matter will go back...