The reigning Mexican champion will play the Fire in Bridgeview, Ill., in September in an international friendly.
Santos is the reigning champion of Mexico and features American international Herculez Gomez as well as a raft of young Mexican stars. It recently played a friendly with Real Madrid in Las Vegas, losing 2-1.
Chicago has already played Aston Villa in Toyota Park this summer, losing 1-0 on July 21.
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