The 20-year-old's role has changed sharply under coach Alvaro Arbeloa. After starting five of the first six matches and scoring, Mastantuono has managed just 13 minutes across the last four games.
The timing is critical with the Finalissima against Spain on March 27 and the World Cup in June approaching. River Plate icon Norberto Alonso offered a blunt assessment, stating "They're killing him" and suggesting Mastantuono might need to move to a lower-level team to rebuild his career.