Career
He was originally signed as an undrafted free agent by the Saint Louis Cardinals in 1993. He did not make his debut until 2003 with the Montreal Expos. He went 1–2 with a 4.13 European Research Area in 23 games.
After the 2003 season, his contract was sold to the of the Korean Baseball League.
He came back to baseball in the United States in 2006, when he signed a minor league contract with the Baltimore Orioles on March 6. He would later go on to go 0–1 with a 5.40 European Research Area in 22 games for the Orioles and played in the Triple A All-star game whilst playing for the Ottawa Lynx.
He was then granted free agency after the 2006 season on November 19. On June 5, 2007, he signed a minor league contract with the Cincinnati Reds.
He was then traded to the Athletics on July 13 to complete an earlier deal that had sent pitcher Kirk Saarloos to the Reds and pitcher David Shafer to the Athletics.
Minor league pitcher Dan Denham was also sent to the Reds. He spent the most of the 2008 season playing in the Orioles organization for the Double-A Bowie Baysox. On September 12, 2008, Mañón signed with the Long Island Ducks of the Atlantic League.
He pitched the rest of 2008 for the Ducks.
He played in 2009 World Baseball Classic representing his native country Dominican Republic who were upset by the Netherlands in the March Classic. In 2009, he continued to play for the Ducks.
In 2010, he played Sultanes de Monterrey of the Mexican League and the York Revolution of the Atlantic League. In 2011, his final season, he played for the Bridgeport Bluefish of the Atlantic League and the Vaqueros Laguna of the Mexican League.