Originally from Dispute Resolution Journal

A grievance and arbitration clause was negotiated into the collective bargaining agreement in baseball in 1968. Under that agreement, the commissioner of baseball serveid as the arbitrator; in 1970, a neutral third party was selected instead. 

The rulings of impartial arbitrators in over 60 cases have had a profound impact on Major League Baseball. The current free-agency system and salary arbitration procedures are a direct result of an arbitrator's decision in the Messersmith-McNally case. Players as well known as Carlton Fisk and Bob Horner and as obscure as Tommy Sandt have brought their grievances to the arbitration table. The issues raised have ranged from discipline and free agency, to payment of incentive bonuses, awarding of World Series rings, and moving expenses. The grievance and arbitration procedure in Major League Baseball has interpreted ambiguous language, resolved grievances, and shaped the language and issues of subsequent collective bargaining agreements.