Bocanegra said it was a permanent deal that was pending MLS approval but did not disclose any other details.
The 24-year-old joined Aberdeen from Norwegian side Stabaek for £850,000 in January 2020 but struggled to establish himself as a first team player at Pittodrie.
The right back, under contract with the Dons until 2024, was loaned to Aberdeen’s partner club Atlanta United last February.
He scored one goal in 13 appearances for Atlanta United and is now set to return to the American club on a long-term basis.
Aberdeen defender Ronald Hernandez ‘to join Atlanta United on permanent deal’ – reports