Berrettini's spot in the draw will be taken by Elias Ymer who is set to face Daniel Altmier.
This win against Zandschulp marked Berrettini's 19th win in his last 20 grass-court matches.
Matteo Berrettini defeated Andy Murray 6-4, 5-7, 6-3 to win the Boss Open final.
Berrettini announced his decision via social media and claimed that he would delay his comeback to compete in the full grass season.
Berrattini lost the Wimbledon final to World no. 1 Novak Djokovic earlier the same day.
Despite falling behind to Matteo Berrettini, Alexander Zverev claimed his first Masters 1000 title since 2018 in Madrid on Sunday.
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