On June 17, 1988, the Chicago Sting selected Simpson in the third round (25th overall) of the Major Indoor Soccer League draft.
[2] The Sting folded a month later and the San Diego Sockers picked up Simpson in the July 1988 dispersal draft.
[3] The Sockers did not sign him and Simpson joined the Chicago Power of the American Indoor Soccer Association in October 1988.
[4] He played each winter indoor season with the Power until February 1995 when he was traded to the Dayton Dynamo for Jim Adams and future considerations.
Intending to play the summer with the Richmond Kickers, he received a call from D.C. head coach Bruce Arena asking if he wanted to join United.
[12] In 2002, Simpson was the goalkeeper coach for D.C. United and spent some time in the same role with the club's Super Y-League team.