Atlanta United confirmed the acquisition of midfielder Santiago Sosa on Friday.

Sosa, 21, is not signing as a Designated Player, and the team didn’t say if he was signed under MLS’ yet-to-be-finalized Under-22 Initiative. He was acquired from River Plate, where he made 21 appearances, on a multi-year contract. He has 13 appearances with Argentina’s U20 national team.

“Santiago is a holding midfielder who understands and reads the game exceptionally well for someone his age,” Atlanta United Vice President and Technical Director Carlos Bocanegra said in a statement from the club. “He broke through into the first team at River last year, experiencing numerous big matches in both Copa Libertadores and the Copa Diego Maradona, in addition to his time with Argentina U-20s.”

The announcement was made almost a week after the player confirmed the move, though a tweet from club President Darren Eales on Friday implied that the club has been waiting on the league to finish the paperwork.

Atlanta United has two other defensive midfielders: Mo Adams, a 24-year-old who made 13 appearances last season, and Eric Remedi, a 25-year-old who made 18 appearances last season. Remedi reportedly is a target of San Jose and a club in Argentina.

Sosa, who once was of interest to Everton, reportedly will be joined in the midfield by Franco Ibarra, another young Argentinian who has said he signed with Atlanta United. The club has yet to confirm the move.