Grillitsch was born on 7 August 1995 in Neunkirchen, Austria. During the 2019/2020 season he played at Hoffenheim under the current head coach of Ajax, Alfred Schreuder. Before the Austrian international moved to Hoffenheim in 2017, he played for Werder Bremen.
UEFA communicated the match schedule for the group stage of the UEFA Champions League on Saturday morning. Ajax opens the six-match series in Amsterdam. On Wednesday 7 September, Rangers FC will be the first opponent at 18:45. The first away game follows six days later against Liverpool. The kick-off of that game is at 21:00.