The perspicacious peregrinator model of Solomon W. Polachek and Francis W. Horvath hypothesizes that individuals decide to migrate based on the size of potential gains. This model is tested using themigration decisions of Major League Baseball players between 1977 and1979. Potential gains are measure d as the differ-ence between earnings with and without migration. A distinction is made between players eligible for free agency and those ineligible so as to a ccount for differences in the level of competition for players' services in diff erent segments of this market. Migration is found tobe related to the expected gain from earnings for players eligible for free agency, but not for those ineli gible.