Novak Djokovic has withdrawn from the Miami Open through injury.
The defending champion has followed Andy Murray in pulling out of the tournament, which begins on Wednesday, because of an elbow problem.
Djokovic wrote Sunday on Facebook: "I have some very disappointing news to share with you regarding the Miami Open tournament.
"My doctor has strongly advised against playing because my elbow injury, that I keep carrying on for months, got worse in the past week.
"I will do everything in my power to recover and do all the necessary therapy to be able to return on court as soon as possible. Sadly, I won't be able to defend my title in Miami this week."
World No. 1 Murray confirmed his withdrawal, also because of an elbow injury, on Saturday.
Djokovic's decision means Murray's lead over the Serbian at the top of the ATP Tour rankings will stretch to around 4,000 points.