Acosta arrived in Washington last week and has been training with D.C. United for the last several days, playing 45 minutes and notching an assist in United’s 1-0 preseason victory over the Tampa Bay Rowdies on Saturday.
The 5-foot-3 playmaker played for Boca Juniors in the 2013-14 season, recording two goals in 25 appearances with the club. He was sent on loan to fellow Argentine Primera side Estudiantes de la Plata last season, playing 27 times and recording 11 starts.
“We are very pleased to have acquired a top young talent on loan from Boca Juniors,” said United GM and VP of soccer operations Dave Kasper said in a team statement. “Luciano is a dynamic creative midfielder who has solid experience the past two seasons in the top Argentine league, and we look forward to quickly integrating him into our group.”
Acosta was signed through the discovery process. According to D.C.’s statement, the New York Red Bulls initially held Acosta’s discovery rights, but they failed to make an offer to Boca Juniors – an MLS requirement if a second team indicates interest. United then obtained the right to engage in talks with Acosta, sending a conditional pick in the 2017 SuperDraft to the Red Bulls prior to opening their official pursuit.