Barco suffered a setback while with the Argentine U-20 team on Wednesday. Atlanta United released the diagnosis and prognosis of the injury on Thursday. Barco will return to Atlanta to begin rehabilitation.

Atlanta United, the defending MLS champs, will start training camp on Jan. 14. Its first two Champions Leagues games are Feb. 21 in Costa Rica at Herediano and Feb. 28 at Kennesaw State in the return leg.