Alexandr Dolgopolov will not play the hard-court season following a knee injury that could require surgery.

"I am really unhappy to announce that I injured my knee in Hamburg and I will probably need a surgery and will be out for 4-6 weeks," he wrote on Instagram. "Disappointing,specially not playing the great event in Umag, the Us series and Davis cup play offs:((( hopefully il be back ASAP."

The 25-year-old from Ukraine fell to Tobias Kamke in the third round of Hamburg. Prior to that, he pulled out of his Queen's Club quarterfinal with a right thigh injury before playing Wimbledon.