Merced was signed as an amateur free agent out of high school at the age of 17 by the Pittsburgh Pirates in 1985. Six years later, he made his major league debut. He played for the Pirates for another six years, where he helped the Pirates win the National League East Division in three consecutive seasons, from 1990 through 1992. He was part of the Astros' 2001 NL Central Division champions.[citation needed]