Novak Djokovic will prepare for the defence of his Wimbledon title by playing doubles in Mallorca.
The Serb has not entered the event's singles draw meaning he will arrive at the All England Club without any grass-court singles match practice.
The Mallorca event is new to the calendar and will be Spain's first Tour-level grass-court tournament.
World number two Daniil Medvedev will also be short of time on grass after losing his opener in Halle.
The Russian lost 7-6 (8-6) 6-3 to Germany's Jan-Lennard Struff in the first round of the German event, one of a number of grass-court events in the run-up to Wimbledon, which starts on 28 June.