Abstract
The invariance interpretation of the Coase Theorem is examined using the mobility behaviour of all offensive players (hitters) in Major League Baseball (MLB) who played from 1949 to 1992. Results indicate that while the institution of the rookie draft did not affect the mobility of players, the mobility of players was altered under free agency. In addition, the period of free agency witnessed mobility behaviours of veteran players which was unlike that mobility under the guidance of owners.