prior to his minor league and major league career, olivo spent many years playing in his native dominican republic. diomedes olivo posted a 55–29 win–loss record in the double-a mexican league from 1955–1959, then made his major league debut with the pirates at age 41 on september 5, 1960. his age at the time of his mlb debut is the oldest with the exception of satchel paige in the post-world war ii era. in his first game, he pitched two scoreless innings of relief against the milwaukee braves, allowing one hit (to eventual hall of famer eddie mathews) and two bases on balls.