The Houston Dynamo have traded Brian Mullan to Colorado for Colin Clark in a swap of midfielders.
Colorado receives a fourth-round selection in the 2013 SuperDraft as part of Wednesday's trade, and Houston gets allocation money.
Clark will miss the rest of this season because of a torn left anterior cruciate ligament, an injury sustained Aug. 7 against San Jose. He also tore an ACL in August 2009.
On Tuesday, the Rapids obtained forward Macoumba Kandji from the New York Red Bulls for midfielder Mehdi Ballouchy.