Philadelphia Union today announced the signing of goalkeeper Karry "Chase" Harrison from the club's USL-Pro affiliate, the Harrisburg City Islanders.

Harrison joins the Union after goalkeeper Thorne Holder was diagnosed with a concussion injury during the Union's reserve match against Columbus Crew. Per Major League Soccer and club policy, the terms of the acquisition will not be disclosed.

Along with recently signed midfielder Morgan Langley, Harrison led the Islanders to the 2011 USL-Pro final, in which Harrisburg lost in a penalty shootout to the Orlando City Lions. During his second season with the club, the goalkeeper registered a total of five shutouts in goal, posting a 1.3 GAA and 8-6-6 record. As a City Islander in 2009, the 'keeper earned eight shutouts, finishing with an 8-4-4 record and a 0.81 GAA, the best mark in the league. For his accomplishments, the fourth City Islander to join the Union received All-League Second-Team honors.