World number one Novak Djokovic has pulled out of next week's Madrid Open, the organisers have confirmed.
No reason has been given for his withdrawal, though in a statement the tournament organisers wish Djokovic a "speedy recovery".
The Serb, 35, has been troubled by a right elbow problem in recent weeks.
Rafael Nadal has already withdrawn from the tournament, which starts on Tuesday, as he continues to struggle in his recovery from a hip injury.
Djokovic was beaten by compatriot Dusan Lajovic in the quarter-finals of the Srpska Open on Friday after admitting his elbow was "not in an ideal condition" going into the tournament.