Nelson was signed out of the Dominican Republic at the age of 17 by the California Angels in 1994. He spent 6 seasons in the California (Anaheim) minor league system before being traded to the San Francisco Giants in 2000. Nelson excelled in the Giants system and eventually spent 3 years with their AAA affiliate in Fresno. Nelson also had stints with the LA Dodgers, Milwaukee Brewers and the Boston Red Sox. Nelson’s professional career spanned 16 seasons, with four of those seasons spent on the MLB 40-man roster. In Nelson’s final season of professional baseball he hit over .400 and led the Calgary Vipers to their first League Championship, and was also named the 2009 Golden Baseball League Player of the Year.