Complex sentence: He was Boston's regular third baseman in --, then spent in a utility role for the Red Sox, St. Louis Cardinals and Baltimore Orioles, and finally playing in the minor leagues for the San Francisco Seals of the Pacific Coast League.
Split into simpler sentences: He was Boston's regular third baseman in --, then spent in a utility role for the Red Sox, St. Louis Cardinals and Baltimore Orioles. In he finally played in the minor leagues, for the San Francisco Seals of the Pacific Coast League.