On July 9, 2008, the Rhinos sent Harrison and Jamil Walker, recently acquired from the Carolina RailHawks, to the Portland Timbers in exchange for Andrew Gregor.
[2] On September 9, 2010, Harrison was added to the D.C. United roster following the release of Andrew Quinn, who underwent knee surgery.
[3] On October 26, the Columbus Crew signed Harrison to a short-term contract to backup Andy Gruenebaum in the postseason after starting goalkeeper William Hesmer suffered a right shoulder fracture.
[4] Harrison was signed by Philadelphia Union on September 23, 2011, to replace injured goalkeeper Thorne Holder as a backup.
After the conclusion of the 2012 season, Philadelphia declined the 2013 option on Harrison's contract and he entered the 2012 MLS Re-Entry Draft.