Marin Cilic is confident of playing at the US Open after confirming he will skip the defence of his Cincinnati Masters title.

The Croatian has been nursing an adductor injury since losing to Roger Federer in the Wimbledon final last month and has already missed the Rogers Cup in Montreal.

Cilic - winner at Flushing Meadows in 2014 - announced on Friday that his lay-off would continue for the time being, but he hopes to be back on court for the final grand slam of the year.

"After having to withdraw from the ATP Masters 1000 event in Montreal, there is another unpleasant task, as I have to announce that I will have to pull out from [the] tournament in Cincinnati as well," he wrote on Facebook.

"I was really eager to play in Cincinnati, where I've won my first career ATP Masters 1000 singles title last year and where I had one of the best performances during my career, but I still don't feel at 100 per cent to compete at the top level and to defend my title there.

"I have already started with my preparation and the progress is going well, but there isn't enough time for me to prepare for Cincinnati and to be completely ready to play there.

"Still, I feel very confident that I will be back in action very soon, and I am looking forward to the upcoming US Open. Once again, thank you all for all the support I am receiving during this injury period! See you soon!"