The Union added goalkeeping depth by acquiring English-born keeper Matt Jones on loan from Belenenses of Portugal's Primeira Liga, the top division.
He will be on loan for the 2016 Major League Soccer season.
Jones holds a U.S. permanent resident card and will not occupy an international spot. That is crucial since the Union don't have one available.
MLS rules allow teams eight international slots, but the slots are allowed to be traded. The Union have seven after sending one international slot last year in the Sheanon Williams trade to Houston.
The Union have seven international players on the roster.