 Locatelli began the season as a starter in the second leg of Milan's Europa League qualification match against CS U Craiova, playing a vital role in Milan's 2–0 win on 3 August 2017.However, Montolivo's eventual recovery combined with the arrival of Lucas Biglia and frequent changes of formation under Vincenzo Montella started to limit his playing time.In November 2017, Montella was dismissed and replaced by Gennaro Gattuso who also viewed Locatelli as more of a backup for either Biglia or Montolivo than a starting lineup player.