Last year's US Open winner has had a tough season so far and went out already in the first round of the French championships at the end of May.
Now the 27-year-old announces that he is over this summer's Olympics in Tokyo.
"2021 did not start as planned and I do not feel ready to play at my best in Tokyo," he wrote on Twitter.
"After talking to my team and analyzing the situation, I have made the very tough decision to withdraw from competing in the Tokyo Olympics."
The Austrian will instead focus on Wimbledon, which starts at the end of June, and then on defending the title in the US Open.
Earlier on Thursday, the Spanish star Rafael Nadal announced that he will be in charge of both Wimbledon and the Olympics in order to "extend his sports career".