Only three original Union players remain after Mwanga's trade back home to Oregon.
Mwanga, 20, was taken with the first overal selection in the 2010 MLS SuperDraft by Philadelphia and managed 12 goals and eight assists in two seasons with the Eastern Conference club.
Coming from Portland, Perlaza, a 26-year-old native of Colombia, joins after two years in Portland. During that time he contributed six goals and two assists. He joins a strong Colombian contingent in Philadelphia with captain Carlos Valdes, Roger Torres, and Lionard Pajoy all hailing from the South American country.
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