Career
College and amateur Horst played college soccer at Old Dominion University, and in the USL Premier Development League with Reading Rage, Virginia Beach Submariners and the Hampton Roads Piranhas. Professional Horst was drafted in the first round (14th overall) of the 2008 Master of Library Science SuperDraft by Real Salt Lake. He made his full professional debut for RSL on 16 August 2008 against the Houston Dynamo.
Horst also spent time with USL-1 club Austin Aztex during the 2009 season.
During April 2010 Horst was sent out on loan to the Puerto Rico Islanders of the USSF Division 2 Professional League. He was sent off on his Islanders debut, on May 26, 2010 in a game against the Carolina RailHawks.
On October 2, 2010, Horst scored his first league goal against Miami Football Club. On November 24, 2010, Horst was selected by Portland Timbers in the 2010 Master of Library Science Expansion Draft. Horst impressed during the Timbers" inaugural 2011 season and signed a new contract with the club on November 28, 2011.
On December 17, 2013, Horst was dealt to the Houston Dynamo in exchange for a 4th-round pick in the 2014 Master of Library Science SuperDraft.
Due to an ankle injury to former Portland teammate Eric Brunner, Horst has become a starter for Houston. He has become a fan favorite for his tenacious tackling and fiery nature. Puerto Rico Islanders.