The 27-year-old made 187 appearances, scoring 20 goals, for the Colombian side, which he joined in 2005.
“Rafael Robayo has an excellent work rate, good defensive energy and will provide support on both sides of the ball,” said Fire head coach Frank Klopas.
“Rafael is a sizable player who can get in and create around the box. He will join our core group in preseason camp as we continue to build toward the 2012 campaign.”
