Jack Clark:
Clark was a big-time slugger who could do little else. He did smash 340 home runs and 1,180 RBI in his career but only hit .267. He played 18 seasons but only made the All-Star Game four times in that span, a testament to the inconsistent nature of his career.
Clark had a few huge seasons for the Giants early on. His best years were with the Cardinals from 1985-1987. Clark then moved on to the New York Yankees, San Diego Padres, and Boston Red Sox. He was never even close to able to recreate the sparse few good years he had.