The Coase Theorem is both one of the simplest and most profound ideas in economics. Coase's insight was first expressed in print as a theorem by George Stigler, following the publication of the famous article "The Problem of Social Cost" by Nobel Laureate Ronald Coase (1960). Stigler stated it thus: "with zero transactions costs, private and social costs will be equal". In this paper the Coase Theorem is approached through the medium of a sports league. While Coase's article dates from 1960, a colleague at Chicago University published a discussion of the market for baseball players in 1956 which almost completely anticipates the more famous paper (Rottenberg (1956)).