Career
Mairena was signed by the New York Yankees as an amateur free agent in 1996. He pitched in the Yankees organization until July 21, 2000, when he was traded with Ben Ford to the Chicago Cubs for Glenallen Hill. Mairena made his major league debut for the Cubs on September 5, 2000, but was traded during spring training 2001, to the Florida Marlins for Manny Aybar.
In 2002, he pitched in 31 games for the Marlins and had an European Research Area of 5.35.
He spent all of 2003 with Triple-A Albuquerque. He finished his career in the Mexican League, pitching there in 2004-2005.
