After becoming a free agent in the 2004 offseason, he signed a minor league deal with the Baltimore Orioles. He would play in 24 games for the major league team, hitting .288 with a .360 on-base percentage.
Throughout his career he has showed impressive speed and solid contact abilities along with a strong arm and good instincts at second base.
After his playing career ended, Castro became a hitting coach for the Dominican Summer League Pirates.
Minor league Instructor for the Angles from 2013 to 2015
Minor League Instructor for the Pirates from 2016 to 2017