Paris: US Open champion Marin Cilic will be unable to defend his Zagreb ATP title next week after failing to recover from a right shoulder injury, organisers said.
"Defending champion @Cilic_Marin has been forced to withdraw from the @ATP_Zagreb due to a shoulder injury. Wishing him a quick recovery," tweeted a tournament spokesman.
The 26-year-old Croatian is still suffering the same right shoulder problem which sidelined him from the Australian Open.
World number nine Cilic, who won the Zagreb tite in 2009, 2010, 2013 and 2014, has not played since the World Tour finals in London in November.
In his absence, fellow Croatian Ivo Karlovic, the world 27, will take the top seeding in Zagreb when the tournament starts on Monday.