The U.S. youth international will compete with Andrew Dykstra for the starting job while Bill Hamid is out.
D.C. United has acquired USA youth international goalkeeper Charlie Horton from the New England Revolution, who put a discovery claim on the player after he left Leeds United in November.
Horton, 21, joins DCU in exchange for general allocation money. The London-born goalkeeper moved to Ohio at a young age before heading back across the pond to join Peterborough United in 2013. He later joined Cardiff City then Championship side Leeds, which he left in November for personal reasons.