US Open champion Marin Cilic has admitted he could miss the Australian Open, the season’s opening Grand Slam tournament, because of an arm injury.

“An MRI exam in Zagreb showed that after some 20 days of therapy the situation with the (right upper arm) injury has improved,” 26-year-old Cilic said through his spokesman, Igor Rajkovic.

“Since there is very little time for a full recovery and training, my appearance at the Australian Open is unfortunately under a big question mark.

“I have not cancelled my appearance in Melbourne. I will leave it for another seven to eight days to see how the situation will develop.”

Some Croatian media reported earlier on Sunday that world number nine Cilic had cancelled his participation at the Australian Open due to the arm injury which occurred several months ago but has deteriorated in the past month.

The Australian Open starts in Melbourne on January 19.