The younger brother of Jose and Tommy Cruz, who also wore Cardinal uniforms, Hector was signed out of Puerto Rico at age 17 and immediately heralded as the best of the three. In 1975 he was TSN Minor League Player of the Year, leading the American Association with 29 HR and 116 RBI. Converted from outfield to third base, he stuck with St. Louis in 1976 and led NL rookies with 13 HR and 71 RBI, but led NL third basemen with 26 errors. He never held another regular job. After bouncing around the NL, he played in Japan for Yomiuri in 1983.
