In 1994, he was named Most Valuable Player of the Metro Atlantic Athletic Conference baseball tournament, where he was the winning pitcher twice in the Peacocks' three-game sweep.

Santos was traded to the Colorado Rockies for José Paniagua in 2002 and acquired by the Texas Rangers before the 2003 season.

Then he signed a minor league contract with the Milwaukee Brewers before being called up for the 2004 season, where he earned his way onto the starting rotation.

After two years with Milwaukee, he made an unusual route via the Kansas City Royals and the Rule 5 draft onto the major-league roster of the Pittsburgh Pirates for the 2006 season.

On January 11, 2008, Santos signed with the San Francisco Giants to a minor league contract with an invitation to spring training.