Eden has the distinction of being the only major leaguer born in Fort Clayton, a former US military base on the Pacific side of the Panama Canal. He attended Southern Illinois University, and as member of the SIU Salukis, was selected third baseman to the All-Tournament Team of the 1971 College World Series. In 1970 and 1971, he played collegiate summer baseball with the Orleans Cardinals of the Cape Cod Baseball League, and won the league's batting title in 1970.