Real Madrid academy product César Palacios will return to Spain for further evaluation after tearing his ACL during the club's preseason U.S. tour, sources told ESPN.
The 19-year-old midfielder suffered the injury five minutes into his first-team debut Wednesday night at Chicago's Soldier Field, a 1-0 defeat to AC Milan.
Subsequent tests confirmed the severity of Palacio's injury, prompting the club's medical staff to put Palacios on a plane back to Madrid to prepare for surgery as soon as possible.
Palacios is one of Real Madrid's most promising prospects, drawing interest from Athletic Club just a few weeks ago.
Álvaro Rodríguez was also injured in the loss to Milan, suffering an ankle sprain. Madrid's medical staff is evaluating whether to send him back to Spain along with Palacios, ESPN has learned.
Real Madrid face Clásico rivals Barcelona in the second match of their preseason tour Saturday in New Jersey.